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WCLN - Science 10
2021-10-13 Page 1 of 35
Chemistry Unit ~ Learning Guide Name:__________________
INSTRUCTIONS
Complete the following practice questions as you work through the related lessons. You are required to have this package completed BEFORE you write your unit test. Do your best and ask questions about anything that you don't understand BEFORE you write the unit test.
2.1 Lab Safety
1. Please indicate whether the following statements are true or false. If the statement is false, please provide a corrected statement in the space provided below it.
a.
If you are unsure about any lab instructions you should proceed (go ahead) with the lab using your best judgment.
b.
Science requires creativity so feel free to create and do any of your own experiments without adult supervision.
c.
You should know the location of all safety and first aid equipment before you proceed with an experiment.
d.
It is only necessary to tie back long hair and avoid loose clothing such as scarves, ties, long necklaces and head/ear phone cords if you are using fire.
e.
You should wear all proper safety protection as instructed by your teacher.
f.
It is fine to proceed with an experiment if you are unsure of the safety symbols (HHPS and WHMIS) as long as you do not see a skull and cross bones label.
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2. Below is a picture of a poorly managed Science 10 laboratory. Please identify and list at least five activities being performed in the picture below that appear unsafe and likely to lead to undue pain and suffering either for the perpetrator or those around him/her.
a.
b.
c.
d.
e.
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Practice: HHPS and WHMIS
1. What does HHPS and WHMIS stand for?
2. Please match the symbol on the left with the appropriate description on the right.
i. _____
a. Indicates explosive such as an aerosol can.
ii. _____
b. Indicates corrosive, contains material that will burn skin, eyes, throat and stomach such as oven cleaner.
iii. _____
c. Indicates product is poisonous and will cause illness or death if ingested such as furniture polish.
iv. _____
d. Indicates flammable and will catch fire easily near heat, sparks or flames such as gasoline and hair spray.
v. _____
e. Indicates materials within the container are dangerous. This symbol usually has further symbols within it such as the corrosive, flammable or poisonous symbol.
vi. _____
f. Indicates the container itself is dangerous. It can explode if heated or punctured leading to flying bits of metal or plastic that can cause serious injury.
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3. Please match the symbol in the middle with the appropriate description on the right by placing the correct letter on the line.
i. _____
a. Oxidizing material
ii. _____
b. Health Hazard
iii. _____
c. Compressed gas
iv. _____
d. Explosive
v. _____
e. Corrosive material
vi. _____
f. Biohazardous infectious material
vii. _____
g. Flammable and combustible material
viii. _____
h. Poisonous and infectious material causing immediate and serious toxic effects
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4. Please find and list at least two products that display the following symbols; either
from your cupboards at home or workplace or the aisles of a grocery store or hardware store.
a. i. ___ ii.
or
b. or i. ii.
c. or i. ii.
d. or i. ii.
5. Where, other than in a school, might you see the following symbol?
6. Where, other than in a school, might you see the following symbol?
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2.2 Naming Compounds – Review
Naming Ionic Compounds Name the following ionic compounds: 1) MgCl2
2) Fe3N2
3) TiBr3
4) Cu3P
5) SnSe2
6) GaAs
7) PbS2
8) BeSe
9) Nb2O3
10) AlAt3
Write the formulas for the following compounds: 11) plutonium (VI) phosphide
12) vanadium (IV) selenide
13) tin (II) nitride
14) cobalt (III) oxide
15) titanium (III) astatide
16) vanadium (V) sulfide
17) chromium (III) hydride
18) lithium iodide
19) lead (II) nitride
20) silver bromide
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Naming Covalent Compounds Name the following covalent compounds, given their formulas: 1) NF3 _______________________________________
2) P2O5 _______________________________________
3) NBr3 _______________________________________
4) SF2 _______________________________________
5) HBr _______________________________________
6) OBr2 _______________________________________
7) BF3 _______________________________________
8) CH4 _______________________________________
9) NO _______________________________________
10) BN _______________________________________
Write the formulas of the following covalent compounds, given their names: 11) carbon disulfide ______________________________________
12) tetraphosphorus decoxide ______________________________________
13) dinitrogen pentoxide ______________________________________
14) silicon triiodide ______________________________________
15) dinitrogen trisulfide ______________________________________
16) tetraiodine nonoxide ______________________________________
17) dichlorine monosulfide ______________________________________
18) sulfur dioxide ______________________________________
19) carbon tetrachloride ______________________________________
20) phosphorus pentabromide ______________________________________
Naming Compounds containing Polyatomic Ions The cations in this first set are all of fixed oxidation state, so no Roman numerals are needed. Write the correct name for:
1) AlPO4 _______________________________________
2) KNO2 _______________________________________
3) NaHCO3 _______________________________________
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4) CaCO3 _______________________________________
5) Mg(OH)2 _______________________________________
6) Na2CrO4 _______________________________________
7) Ba(CN)2 _______________________________________
8) K2SO4 _____________________________________
9) NaClO4 _______________________________________
10) NH4NO3 _______________________________________
The following compounds involve the use of a polyatomic ion. The cations are all of variable oxidation state (multivalent), so Roman numerals are needed.
Write the correct name for:
11) Sn(NO3)2 _______________________________________
12) FePO4 _______________________________________
13) Cu2SO4 _______________________________________
14) Ni(CH3COO)2 _______________________________________
15) HgCO3 _______________________________________
16) Pb(OH)4 _______________________________________
17) Cu2Cr2O7 _______________________________________
18) Cu(ClO3)2 _______________________________________
19) FeSO4 _______________________________________
20) Hg(ClO4)2 _______________________________________
Write the correct formula for:
21) potassium chlorite _______________________________________
22) tin (II) sulfate _______________________________________
23) aluminum permanganate _______________________________________
24) lead (II) nitrate _______________________________________
25) magnesium phosphate _______________________________________
26) copper (I) bisulfite _______________________________________
27) calcium permanganate _______________________________________
28) iron (III) bicarbonate _______________________________________
29) sodium carbonate _______________________________________
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30) manganese (II) sulfate _______________________________________
2.3 NOTES: Conservation of Mass in Chemical Equations
The Law of Conservation of Mass
• In chemical reactions, atoms are
• Developed by Antoine Lavoisier and his wife Marie-Anne in the 1700s
• = ______________________________
Chemical reactions result in .
• Chemical changes occur when new substances are created.
• The original substance(s), called , change into new
substance(s) called .
Chemical change means _______________________are created.
• BUT no new matter is created or destroyed; atoms are just _________________
• ________________________________________________________________
• John Dalton, 200 years ago, realized that atoms simply rearrange themselves during
chemical reactions.
• ________________________________________________________________
Chemical reactions can be written in different ways.
• A : o Nitrogen monoxide + oxygen
"⎯⎯$ nitrogen dioxide
• A : o 2NO(g) + O2(g)
"⎯⎯$ 2NO2(g)
Coefficients (big numbers in front of compounds) - indicate the ratio of compounds in the reaction - here, there is as much NO and NO2 than there is O2.
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Polyatomic Elements, Diatomic Elements and Common Names Elements and Compounds you should know
o Most elements occur naturally as singlets but there are some that do not you should be aware of.
o Be aware of these polyatomic elements: o The “special seven” are all diatomic elements you should memorize:
• Several common covalent molecules containing hydrogen have common names that
that you should memorize as the name gives you no clue as to the formula. • methane = , glucose = , ethane = , ammonia =
The pink shaded area in the picture below shows the diatomic atoms.
Writing Chemical Equations The simplest form of chemical equation is a
• Not much information other than the elements/compounds involved • Potassium metal + oxygen gas --> potassium oxide • reactants appear on the left of the arrow and products appear on the right
A skeleton equation shows the formulas of the elements/compounds
• • K(s) + O2(g)
"⎯⎯$ K2O(s)
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A balanced chemical equation • ensures that the number of each atom is the same on both sides of the reaction arrow • always use the smallest whole number ratio
• 4 K(s) + O2(g)
"⎯⎯$ 2 K2O(s)
State of matter - Letters indicate the state of each compound • (aq) = • (s) = • (l) = • (g) =
Balancing Chemical Equations Because of the Law of Conservation of Mass, we can count atoms and use math to balance the number of atoms in chemical equations.
• Word equation: methane + oxygen "⎯⎯$ water + carbon dioxide
o Skeleton equation: CH4(g) + O2(g) "⎯⎯$ H2O(l) + CO2(g)
o To balance the compounds, take note of how many atoms of each element occur on each side of the reaction arrow:
1 Carbon, 4 Hydrogen, 2 Oxygen
"⎯⎯$ 1 Carbon, 2 Hydrogen, 3 Oxygen
Double the quantity of Hydrogens in the products. Place a 2 in front of H2O. 1 Carbon, 4 Hydrogen, 2 Oxygen
"⎯⎯$ 1 Carbon, 4 Hydrogen, 4 Oxygen
Now double the quantity of Oxygen in the reactants. Place a 2 in front of O2. • Balanced equation: CH4(g) + 2 O2(g)
"⎯⎯$ 2 H2O(l) + CO2(g)
Balance chemical equations by following these steps:
• Trial and error will work, but can be very inefficient • Balance , elements last • Balance one compound at a time • Only add coefficients; NEVER change subscripts! • If appear in more than one place, attempt to balance them • Polyatomic ions (such as SO42–) can often be • Always double-check after you think you are finished!
Balance the following:
A. ___ Fe + ___ Br2 "⎯⎯$ ___ FeBr3
Let’s start with Br. The LCM of 2 and 3 is 6. Place a 3 in front of Br2 and a 2 in front of FeBr3.
___ Fe + 3 Br2 "⎯⎯$ 2 FeBr3
Next, balance Fe. Place a 2 in front of Fe. Voilà! 2 Fe + 3 Br2
"⎯⎯$ 2 FeBr3
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B. ___ Sn(NO2)4 + ___ K3PO4 "⎯⎯$ ___ KNO2 + ___ Sn3(PO4)4
It’s best to begin with the polyatomic ions, such as PO4. Place a 4 in front of K3PO4. ___ Sn(NO2)4 + 4 K3PO4
"⎯⎯$ ___ KNO2 + ___ Sn3(PO4)4
Notice that there are now 12 K in the reactants. Place 12 in front of KNO2. ___ Sn(NO2)4 + 4 K3PO4
"⎯⎯$ 12 KNO2 + ___ Sn3(PO4)4
Next, balance the NO2 in the reactants. Place a 3 in front of Sn(NO2)4. It’s now a balanced equation!
3 Sn(NO2)4 + 4 K3PO4 "⎯⎯$ 12 KNO2 + Sn3(PO4)
C. ___ C2H6 + ___ O2
"⎯⎯$ ___ CO2 + ___ H2O
For combustion of carbohydrates (CH compounds), it is always best to begin with Carbon and Hydrogen, ending with Oxygen. Begin by placing a 2 in front of CO2 to balance the C. Then, place a 3 in front of H2O to balance the H. ___ C2H6 + ___ O2
"⎯⎯$ 2 CO2 + 3 H2O
Count the number of O in the product and divide this number by 2. In the products, there are 7 O. Place %
& in front of O2.
1 C2H6 + %& O2
"⎯⎯$ 2 CO2 + 3 H2O
Since we are NOT allowed to have fractions in a balanced equation, simply double all quantities in the equation.
2 C2H6 + 7 O2 "⎯⎯$ 4 CO2 + 6 H2O
2.3 PRACTICE - Balancing Chemical Equations
1. Please Complete Check Your Understanding - Balancing.
2. In a chemical reaction, what do we call the original substances?
3. In a chemical reaction, what do we call newly made substances?
4. What are the three common states of matter?
5. If the mass of all the reactants in a chemical reaction is 100g, what will the mass of all the products be?
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6. Please balance the following reactions. Use the table to show your work.
___ Mg + ___ HCl "⎯⎯$ ___ MgCl2 + ___ H2
Reactants Products
___ Mg + N2 "⎯⎯$ __ Mg3N2
Reactants Products
___ Ba + ___ HBr
"⎯⎯$ ___ BaBr2 + ___ H2
Reactants Products
___ BiCl3 + ___ H2S "⎯⎯$ ___ Bi2S3 + ___ HCl
Reactants Products
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___ Br2 + ___ KI "⎯⎯$ ___I2 + ___ KBr
Reactants Products
___ Fe + ___ O2 "⎯⎯$ ___ Fe2O3
Reactants Products
___ CaO + ___C "⎯⎯$ CaC2 + ___ CO2
Reactants Products
___ Bi2O3 + ___ H2
"⎯⎯$ _Bi + ___ H2O
Reactants Products
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___ P4 + I2 "⎯⎯$ PI3
Reactants Products
Sn + ___ NaOH
"⎯⎯$ ___Na2SnO2 + ___ H2
Reactants Products
C6H12O6 + __ O2 "⎯⎯$ CO2 + ___ H2O
Reactants Products
C8H18 + ___ O2 "⎯⎯$ CO2 + H2O
Reactants Products
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7. What are the seven diatomic molecules? It is strongly recommended you memorize these. 2.4 NOTES: Energy Changes in Chemical Reactions Exothermic Reactions
These are reactions which ___________energy. Energy in chemical reactions is measured in _____________ (kJ). Consider the following hypothetical reaction:
x2 + y2 "⎯⎯$ 2xy
50 kJ of energy are required to _____________ that hold the x's and y's together in their respective molecules, but 100 kJ is released when xy forms.
50 kJ + x2 + y2 "⎯⎯$ 2xy + 100 kJ
simplified
x2 + y2 "⎯⎯$ 2xy + 50 kJ
The ______________ is that 50 kJ of energy are released.
Reactions of this sort which produce energy are called _____________ reactions. "Exo" means "out" and "therm" refers to _______. So, "exothermic" means that heat is coming out, or being produced.
Reactants → Products + _______________
An example of an exothermic reaction occurs during _________________ in animals and plants. The reaction involves "burning" sugar (glucose C6H12O6 (s)) to produce energy. Oxygen from the air is required.
C6H12O6(s) + 6 O2(g) "⎯⎯$ 6 CO2(g) + 6 H2O(l) + 2 803 kJ
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Endothermic Reactions There is a net requirement or ______________________ in some chemical reactions. The bond breaking process in the reactants requires more energy than is released in total. Energy from an external source must be absorbed.
_______________ + Reactants "⎯⎯$ Products
Such reactions which absorb energy are called _______________ reactions. ("Endo" means "into.")
Plants have the ability to use the sun's energy to convert carbon dioxide and water into glucose and oxygen. This is the opposite process of cellular respiration and is called _____________________:
6 CO2(g) + 6 H2O(l) + 2 803 kJ (from the sun) → C6H12O6(s) + 6 O2(g) 2.4 PRACTICE: Energy in Chemical Reactions
Before you complete the practice below read Energy Changes During Chemical Reactions.
1. State whether each of the following are exothermic or endothermic.
Reaction or Event
Exo or Endo
2 C8H18 + 25 O2
"⎯⎯$ 16 CO2 + 16 H2O + 10 110 kJ
Ba(OH)2 + 2 NH4Cl + 430 kJ
"⎯⎯$ BaCl2 + 2 NH4OH
6 SOCl2 + CoCl2•6H2O
"⎯⎯$ CoCl2 + 12HCl + 6 SO2 DH =
+360 kJ
Mn(s) + 2 HCl(aq)
"⎯⎯$ MnCl2(aq) + H2(g) DH = −221 kJ
Boiling Water
Metabolizing Food
The energy possessed by the products is greater than the
energy possessed by the reactants.
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2.5 NOTES: Types of Chemical Reactions
Synthesis - Synthesis reactions are also known as . Definition: A synthesis reaction is when (usually elements) join to form a . where A and B represent . The elements may form , like these:
o Sodium metal and chlorine gas combine to form sodium chloride. 2 Na + Cl2
"⎯⎯$ 2 NaCl
o Magnesium metal reacts with oxygen gas to form magnesium oxide. 2 Mg + O2
"⎯⎯$ 2 MgO
Or the elements may form , like this:
o Nitrogen gas and oxygen gas join to form dinitrogen monoxide. 2 N2 + O2
"⎯⎯$ 2 N2O
Decomposition - Decomposition reactions are the . Definition: A decomposition reaction is when into two or more products (often elements).
• where A and B represent elements Ionic compounds may decompose to produce elements, like this:
• Table salt, sodium chloride, can be broken down into sodium metal and chlorine gas by melting salt at 800ºC and running electricity through it.
2 NaCl "⎯⎯$ 2 Na + Cl2
Covalent compounds may decompose into elements, like this: • By running electricity through water, the water
molecules decompose into hydrogen and oxygen gases. 2 H2O
"⎯⎯$ 2 H2 + O2
Single Replacement - Single replacement reactions replace with a added as a reactant. Definition: A single replacement reaction is when a compound and an element react, and the element switches places with part of the original compound. Positive ions will only replace a positive ion and negative ions will only replace a negative ion.
o where A is a metal, or o where A is a non-metal
When A is a metal:
• Aluminum foil in a solution of copper (II) chloride produces solid copper and aluminum chloride.
Al + CuCl2 "⎯⎯$ Cu + AlCl3
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When A is a non-metal: • When fluorine is bubbled through a sodium iodide solution, iodine and sodium fluoride
are produced. F2 + NaI
"⎯⎯$ I2 + NaF
Double Replacement - Double replacement reactions reacting together to form two new compounds. Definition: Double Replacement is when , with elements switching places between the original compounds.
• Two elements switch partners. general form:
• When potassium chromate and silver nitrate react, they switch partners to form silver chromate and potassium nitrate.
K2CrO4 + AgNO3 "⎯⎯$ Ag2CrO4 + KNO3
Neutralization - Neutralization reactions occur when an .
Definition: Neutralization is when an (most compounds starting with H) and a (most compounds ending in OH) react.
o o HX + MOH
"⎯⎯$ MX + H2O where X and M are elements
• Sulphuric acid is used to neutralize calcium hydroxide:
H2SO4 + Ca(OH)2 "⎯⎯$ CaSO4 + 2 H2O
• Phosphoric acid helps to neutralize the compounds that cause rust, such as iron (II) hydroxide.
H3PO4 + 3 Fe(OH)2 "⎯⎯$ Fe3(PO4)2 + 6 H2O
Combustion - Combustion reactions occur when a with to release and produce an Also sometimes referred to as hydrocarbon combustion
Definition: A combustion reaction is when a hydrocarbon reacts with Oxygen to produce Water and Carbon Dioxide
• where X and Y represent integers
o Natural gas (methane) is burned in furnaces to heat homes. CH4 + O2
"⎯⎯$ CO2 + 2 H2O
o An acetylene torch is used to weld metals together 2 C2H2 + 5 O2
"⎯⎯$ 4 CO2 + 2 H2O
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o Carbohydrates like glucose combine with oxygen in our body to release energy. C6H12O6 + 6 O2
"⎯⎯$ 6 CO2 + 6 H2O
2.5 PRACTICE: Types of Chemical Reactions
1. For each of the 6 types of reactions provide a definition, a general reaction
involving letters and an example. The first one is done for you.
Synthesis
Definition
A synthesis reaction is when two or more reactants (usually
elements) join to form a compound.
General Equation
A + B
"⎯⎯$ AB
Example
2 Na + Cl 2
"⎯⎯$ 2 NaCl
Decomposition
Definition
General Equation
Example
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Single Replacement
Definition
General Equation
Example
Double Replacement
Definition
General Equation
Example
Neutralization
Definition
General Equation
Example
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Combustion
Definition
General Equation
Example
2. Classify the following reactions as synthesis (SYN), decomposition (DEC), single replacement (SR), double replacement (DR), neutralization (NEU) or combustion (COMB). IF you want extra balancing practice then also balance the reactions.
a. _____ __H2O2 "⎯⎯$ __ H2O + __O2
b. _____ __HCl + __NaOH
"⎯⎯$ __NaCl + __H2O
c. _____ __Al + __NiBr2 "⎯⎯$ __AlBr3 + __Ni
d. _____ __N2 + __H2 "⎯⎯$ __NH3
e. _____ __AgNO3 + __KCl "⎯⎯$ __AgCl + __KNO3
f. _____ __C6H6 + __O2
"⎯⎯$ __CO2 + __H2O g. _____ __Mg + __HCl
"⎯⎯$ __MgCl2 + __H2
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h. _____ __Mg + __N2
"⎯⎯$ __Mg3N2 i. _____ __Ba + __HBr
"⎯⎯$ __BaBr2 + __ H2
j. _____ __BiCl3 + __H2S
"⎯⎯$ __Bi2S3 +__ HCl
k. _____ __Br2 + __KI "⎯⎯$ __I2 + __KBr
l. _____ __Fe + __O2 "⎯⎯$ __Fe2O3
m. ____ C4H10 + __O2 "⎯⎯$ __CO2 + __H2O
n. ____ __CaO + __C
"⎯⎯$ __CaC2 +__O2
o. ____ __LiOH + __ HBr "⎯⎯$ __ LiBr +__H2O
p. ____ __Bi2O3 + __H2 "⎯⎯$ __Bi + __H2O
q. ____ __P4 + __I2 "⎯⎯$ __PI3
r. ____ __H2O2 "⎯⎯$ __H2O + __O2
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s. ____ __C6H12O6 + __O2
"⎯⎯$ __CO2 + __H2O t. ____ __NH4NO3
"⎯⎯$ __N2O + __H2O u. ____ __Al4C3 + __H2O
"⎯⎯$ __CH4 + __Al(OH)3
v. ____ __Ca(OH)2 + __CO2
"⎯⎯$ __Ca(HCO3)2
w. ___ __Pb(NO3)2 "⎯⎯$ __PbO + __NO2 + __O2
x. ____ __C8H18 + __O2 "⎯⎯$ __CO2 + __H2O
y. ____ ___ H2SO4 +___ Be(OH)2
"⎯⎯$ ___ H2O + ___ BeSO4
Summary of Chemical Reactions.
Type of reaction Reactants "⎯⎯⎯$ Products Description of Reactant(s)
Synthesis 𝑋 + 𝑌"⎯⎯$ 𝑋𝑌 Two elements combine.
Decomposition 𝑋𝑌"⎯⎯$ 𝑋 + 𝑌 Only one reactant.
Single Replacement X is a metal X is a non-metal
𝑋 + 𝑌𝑍
"⎯⎯$ 𝑌 + 𝑋𝑍
𝑋 + 𝑌𝑍"⎯⎯$ 𝑍 + 𝑋𝑌
One element and one compound.
Double Replacement 𝑊𝑋 +𝑌𝑍"⎯⎯$ 𝑊𝑍 + 𝑌𝑋 Two compounds.
Neutralization 𝐻𝑋+ 𝑌𝑂𝐻"⎯⎯$ 𝑌𝑋 + 𝐻&𝑂 Acid and a base.
Combustion 𝐶0𝐻1 +𝑂& "⎯⎯$ 𝐶𝑂& +𝐻&𝑂 Carbohydrate and oxygen.
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2.6 NOTES: Acids, Bases and Salts
General Information Acids and bases are .
• Many familiar compounds are acids or bases. • Classification as acids or bases is based on .
Acids and bases can be very !
• Both can be very corrosive. o try to identify an acid or base by !
The strength of acids and bases in measured on the pH scale
• pH below 7 = acidic, pH above 7 = basic, pH 7 = neutral 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
__________ ___________ ____________
• Each on the pH scale indicates more acidic o For example, pH 4 is ten times more acidic than pH 5 o
pH Indicators
The pH of acids and bases cannot be determined by sight. • Instead, pH is other chemicals called , or
by a pH meter that measures the electrical conductivity of the solution. pH indicators based on the solution they are placed in.
• is the most common indicator, used on litmus paper. • Two colours of litmus paper: Blue = basic and Red = acidic. • Blue = pH above 7, Red = pH below 7 • contains many indicators that turn different
colours at different pH values (can be in liquid form, or on paper strips like litmus) • A uses to measure
how solutions conduct electricity • Indicators change colour at different pH values, so
indicators are used to identify values • Bromothymol blue for pH 6 - 7.6, phenolphthalein for pH 8.2 - 10 • Many natural sources, such as beets and cabbage, are also indicators
Acids
If you know a , you may be able to identify it as an acid.
• Acids often behave like acids only when dissolved in water
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• Therefore, acids are often written with subscript (aq) = aquatic = water
The chemical formula of an acid usually starts with • Acids with a carbon usually have the C written first.
o = hydrochloric acid, = nitric acid, = acetic acid
Naming acids • For Acids formed from
the periodic table: Hydrogen + …-ide = Hydro…ic acid o HF(aq) = hydrogen fluoride =
• For Acids formed from .
Hydrogen + …-ate = …ic acid o H2CO3(aq) = hydrogen carbonate =
• For Acids formed from .
Hydrogen + …-ite = …ous acid o H2SO3(aq) = hydrogen sulphite =
Bases If you know a compound’s chemical formula, you may be able to identify it as a base.
• Bases, like acids, often behave like bases only when dissolved in water • Therefore, bases are often written with subscript (aq) = aquatic = water
The chemical formula of a base usually ends with ___________________.
•Examples of common bases • NaOH(aq) • Mg(OH)2(aq) • Ca(OH)2(aq) • NH4OH(aq)
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Naming Bases • To name a base you simply name
o NaOH(aq) - Sodium hydroxide o Mg(OH)2(aq) - Magnesium hydroxide
Production of Ions Acids and bases because they release ions in solution.
• Acids release • Bases release
The pH of a solution refers to the concentration of (H+/OH-) ions it has.
• Square brackets are used to signify concentration, [H+(aq)], [OH–(aq)] o High [H+(aq)] = , very acidic o High [OH–(aq)] = , very basic
• A solution cannot have BOTH
high [H+(aq)] and [OH–(aq)]; they cancel each other out and . This process is called .
• H+(aq) + OH–(aq) "⎯⎯$ H2O(l)
Properties of Acids & Bases
Property Acid Base TASTE: NEVER taste chemicals in the laboratory.
Taste sour: for example, lemons, limes and vinegar.
Taste bitter: for example, quinine in tonic water
TOUCH: NEVER touch chemicals with bare hands. Use appropriate gloves if touch is required.
Many acids are corrosive and may cause burn to the skin. Acid in batteries is an example.
Slippery: many bases are corrosive and may cause burn to the skin. Lye (NaOH) is an example.
INDICATOR tests
Blue litmus paper turns red. Phenolphthalein is colourless in acidic solutions.
Red litmus paper turns blue. Phenolphthalein is pink is a basic solution.
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REACTION with some metals, i.e. magnesium or zinc
Corrode metals.
No reaction.
ELECTRICAL conductivity
Conductive.
Conductive.
pH
Below 7.
Above 7.
ION production (H+) ions are produced when dissolved in a solution.
(OH¯) ions are produced when dissolved in a solution.
2.6 PRACTICE: Acids, Bases and Salts 1. Please Complete Check Your Understanding – Acids and Bases. 2. Water is a neutral compound. What is the pH of water? 3. How many times more acidic is pH 2 than pH 4? 4. Name two methods used to measure pH. 5. What is the most common indicator? Describe its colour in acid and base. 6. What does it mean when you see (aq)? 7. What letter do most acids start with?
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8. What is different about the position of that letter if an acid starts with a C? 9. Name the following acids:
Formula Name
HBr
H2S
HNO2
HNO3
HClO4
H2CO3
CH3COOH
10. How can you recognize that a given formula is a base?
11. Name the following bases:
Formula Name
KOH
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Al(OH)3
NH4OH
12. Why do acids and bases make good electrical conductors when dissolved in water?
13. What ion does an acid release? What ion does a base release?
14. Why is it not possible to have a solution that is both highly acidic AND highly basic? What is the process called that prevents this from happening?
15. Fill in the table below with the most important information. Do not simply copy everything from the website.
Property Acid Base
Taste
Touch
Colour o f Litmus
Reaction with metal
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pH
2.6 NOTES: Salts
General Information
Salts are formed when . • Salts are also produced when oxides or carbonates react with acids, or when metals
react with acids.
Table salt, , is found in seawater, salt lakes or rock deposits. • Salt was once very valuable as a commodity. • Iodine is now added to salt to minimize goiter (a disease of the thyroid)
NaCl is only one kind of salt
• A salt is made up of a from a base and • Salts are found in many things
o o o
Neutralization & Oxides Neutralization reactions occur when an react to produce a .
• HCl(aq) + NaOH(aq) "⎯⎯⎯$ NaCl(s) + H2O(aq)
Metal oxides react with water to form bases.
• Na2O(s) + H2O(l) "⎯⎯$
Non-metal oxides react with water to form acids
• SO2(g) + H2O(l) "⎯⎯$
• Non-metal oxides are formed from the burning of fossil fuels o Add water in the atmosphere =
Acids with Metals & Carbonates Acids and Metals
• The most reactive metals , react vigorously with water and acids.
• All other metals are than those in groups 1 and 2. • When metals do react with acids is usually released • 2HCl(aq) + Mg(s)
"⎯⎯$ MgCl2(s) + ________________
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Acids and Carbonates • (-CO3) , protecting locations
with natural carbonate supplies from acid precipitation. • H2SO4(aq) + CaCO3(s)
"⎯⎯$ CaCO2(s) + H2O(aq) + CO2(g)
sulphuric acid + calcium carbonate --> calcium carbonite + water + carbon dioxide 2.6 PRACTICE: Salts Please Complete Check Your Understanding – Salts. 1. What type of compounds are salts?
2. What are the three types of reactions that produce salts? 3. What is the formula of table salt? 4. Name 5 things that may contain a salt?
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5. Predict the products of each of the following reactions using the examples in the notes as a guide:
Reactants Products
H2S(aq) + Ca(OH)2(aq) "⎯⎯$
(Acid) (base)
CaO(s) + H2O(l) "⎯⎯$
(metal oxide) (water)
NO2(g) + H2O(l) "⎯⎯$
(non-metal oxide) (water)
6. What non-metal oxide is the main cause of acid rain?
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Student Answer Key: Please note that answers are directly from the online notes for the NOTES sections. Select answers are given for the PRACTICE sections.
2.1 Answers for Safety Section of Learning Guide: S1 1 a) F – ask first, b) F –only do experiment as provided with supervision, c) T. 2 : Answers will vary. S2 1: Household Hazardous Products Symbols, Workplace Hazardous Materials Information System. 2: i) f, ii) a, iii) e. 3 i) c, ii) a, iii) e, iv) b. 4: answers will vary. 5: answers will vary, 6: answers will vary. 2.2 Naming Compounds – Review Naming ionic compounds
1. magnesium chloride, 3. titanium(III) bromide, 5. tin(IV) selenide, 7. lead(IV) sulfide, 8. beryllium selenide, 9. niobium(III) oxide, 11. PuP2 13. Sn3N2 15. TiAt3 17. CrH3 19. Pb3N2 Naming covalent compounds 1. nitrogen trifluoride, 3. nitrogen tribromide, 4. sulfur difluoride, 5. hydrobromic acid (or hydrogen bromide), 8. carbon tetrahydride (or methane), 9. nitrogen monoxide, 10. boron nitride, 11. CS2, 13. N2O5, 15. N2S3, 17. Cl2S, 19. CCl4, Naming Polyatomic compounds 1. aluminum phosphate 3. sodium bicarbonate or sodium hydrogen carbonate 5. magnesium hydroxide 7. barium cyanide 9. sodium perchlorate 11. tin (II) nitrate 12. iron (III) phosphate 14. nickel (II) acetate 15. mercury (II) carbonate 17. copper (I) dichromate 18. copper (II) chlorate 20. mercury (II) perchlorate 21. KClO2 23. Al(MnO4)3 25.Mg3(PO4)2 26. CuHSO3 28. Fe(HCO3)3 30. MnSO4 2.3 Answers for Balancing Chemical Equations: 2) Reactants, 4) solid, liquid, gas, 6) Mg + 2 HCl
"⎯⎯$ MgCl2 + H2 ; 2 BiCl3 + 3 H2S
"⎯⎯$ Bi2S3 + 6 HCl ; 4 Fe + 3 O2
"⎯⎯$ 2 Fe2O3 ;
2 CaO + 5 C "⎯⎯$ 2 CaC2 + CO2 ; Bi2O3 + 3 H2
"⎯⎯$ 2 Bi + 3 H2O ; C6H12O6 + 6 O2 "⎯⎯$ 6 CO2 + 6 H2O;
2 C8H18 + 25 O2 "⎯⎯$ 16 CO2 + 18 H2O
7) N2, O2, H2, Cl2, Br2, I2, F2 2.4 Answers for Energy: 1. State whether each of the following are exothermic or endothermic. Answers: (i) Exo, (iii) Endo, (v) Endo, (vi) Exo, (vii) Endo. 2.5 Answers for Types of Chemical Reactions: 1) Answers directly from online notes, 2) Note that numbers represent coefficients of balanced equations in order. a) Dec 2,2,1 b) Neu 1,1,1,1 c) SR 2,3,2,3 d) Syn 1,3,2 e) DR 1,1,1,1 f) Comb 2,15,12,6 g) 1,2,1,1 h) 3,1, 1 i) SR 1,2,1,1 j) DR 2,3,1,6 k) 1,2,1,2 l) 4,3,2 m) 2,13, 8,10 n) SR 2, 4, 2, 1 o) Neu 1,1,1,1 p) 1,3,2,3 q) 1,6,4 r) 2,2,1 s) Comb 1,6,6,6 t) Dec 1,1,2 u) 1,12,3,4 v) Syn 1,2,1 w) Dec 2,2,4,1 x) 2,25,16,18 y) 1,1,2,1
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2.6 Answers for Acids and Bases: 3) 100x, 6) aqueous or dissolved in water, 8) the H will be at the end of the chemical formula, 9) Hydrobromic acid, Hydrosulfuric acid, Nitrous acid, Nitric acid, Perchloric acid, Carbonic acid, Acetic acid, 11) Potassium hydroxide, Aluminum hydroxide, Ammonium hydroxide. 14) acids and bases when added together neutralize each other, the H+ and OH- cancel each other out 15) see table from online notes.
2.6 Answers for Salts:
2) an acid and a base reacting together, an acid reacting with an oxide or a carbonate, an acid reacting with a metal 5) CaS + 2H2O, Ca(OH)2, HNO2 + HNO3, 6) Sulfur dioxide
