Significant Figures, Units,Conversions, Density

Keep your brains on and your calculators alert!

Significant Figure Rules

•Nonzero integers are significant

•Leading zeros are never significant

•Captive zeros are always significant

•Trailing zeros are only significant when there is a decimal present in the number

•Exact numbers have an infinite number of significant figures

Significant Figures•60.0000

•400000

•7.023

•0.090

•0.0002

•3.05 x 105

Significant Figure Rulesfor Addition and

Subtraction

•The answer has the same number of decimal places as the least precise measurement.

7.2 + 4.841 =

3.142 - 1 =

Significant Figure Rulesfor Multiplication and

Division

•The number of SF in the answer can be no greater than the number of SF in value with the least number of SF.

7.2 x 4.841 = 3.142 ÷ 1 =

Temperature Conversions

•Fahrenheit to Celsius:

(F 32F) x 5C / 9F

•Celsius to Fahrenheit:

(C x 9F / 5C) + 32F

Temperature Conversions

•Celsius to Kelvin:

C + 273

•Kelvin to Celsius:

•K 273

How many SF are in the following:

a.900.0

b.3.0020

c.6.020 x 10-2

d.2007

e. 6 x 105

f. 47,000

g.0.0001

h.0.0098030

a.900.0

b.3.0020

c.6.020 x 10-2

d.2007

e. 6 x 105

f. 47,000

g.0.0001

h.0.0098030

Round the following to 3 SF:

Perform the following using applicable SF rules:

a. 2.0 + 1.650

b. 12 0.00999

c. (8.040 x 10-3) x (9 x 106)

d. 400 3.5

Measurement

•mass--kg•length--m•time--s•temperature--K•amount of substance--mol

Measurement Prefixes

•giga(G)– 10-9

•mega(M)—10-

6

•kilo(k)– 10-3

•hecto(h)– 10-2

•deka(da)– 10-

1

•deci(d)-- 101

•centi(c)-- 102

•milli(m)-- 103

•micro(µ)-- 106

•nano(n)-- 109

•Accuracy

•Precision

•Random error

•Systematic error

Metric-Metric Conversions

360 mm = _____m

4.25 x 10−5 ML = _____mL

325 mg = _____kg

Metric-English Conversions

360 mm = _____in

4.25 x 10−5 ML = _____gal

325 mg = _____lb

100 m/s = _____mi/h

Density

D = mass/volume

Vrectangular prism = l x w x h

Vcylinder = πr2h

Vsphere = (4/3)πr3

Density

A square piece of cobalt glass (glass with cobalt ions mixed into it) has a mass of 12.228 g.

Its dimensions are 50 mm x50 mm x 2 mm.

What is its density in g/cm3?

Density

A cylindrical piece of aluminum metal has a diameter of 12.5 mm and a mass of 16.559 g.

The density of aluminum is known to be 2.70 g/cm3.

What is its length in mm?

Density

A steel solid sphere has a diameter of 70 cm.

The density of this steel is known to be 7.80 g/cm3.

What is its mass in g?