Chapter 2

30°C 30°F

SI unit

Measuring Volume

We will be using graduated cylinders to find the volume of liquids and other objects.

Read the measurement based on the bottom of the meniscus or curve. When using a real cylinder, make sure you are eye-level with the level of the water.

What is the volume of water in the cylinder? _____mL

What causes the meniscus?

A concave meniscus occurs when the molecules of the liquid attract those of the container. The glass attracts the water on the sides.

Measuring Liquid Volume

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Pay attention to the scales for each cylinder.

Measuring Solid Volume

10 cm

9 cm

8 cm

We can measure the volume of regular object using the formula length x width x height.

_____ X _____ X _____ = _____

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We can measure the volume of irregular object using water displacement.

Amount of H2O with object = ______

About of H2O without object = ______

Difference = Volume = ______

How hot? How cold? direction of Heat Transfer

Celsius – 0 0C Freezing Point of Water 100 0C Boiling Point of Water

Kelvin = C° + 273 No degree signs are used O Kelvin = -273.150 C

▪ coldest possible temperature

Length – size meter (m)

Mass – amount of matter Kilogram (kg) or gram (g)

Volume – space something takes up Liter (l) or centimeters cubed (cm3)

Temperature – amount of heat Kelvin (K) = celsius + 273

Measure of how much matter is squeezed into a given space

density = mass volume

A block of wood and a block of steel have the same volume

What happens to the density of an object if it is cut into pieces?

Which has the greater density, a single uranium atom or Earth?

coefficient x 10 raised to a power

Single gram of hydrogen 602,000,000,000,000,000,000,000

molecules = 6.02 x 1023 molecules

Mass of an atom of gold 0.000000000000000000000327 grams = 3.27 x 10-22 grams

36,000 3.6 x 104

503,000,000 5.03 x 108

0.00076 7.6 x 10-4

The valid digits of a number  In measurement: includes all of the

digits that are known, plus a last digit that is estimated

Significant: nonzero digits final zeros after the decimal points zeros between two other significant

digits

Not significant zeros used solely for spacing the

decimal point are not significant.

each have only two sig figs 0.0071 meter 0.42 meter 0.000099 meter

7.1 x 10-3 meter4.2 x 10-1 meter9.9 x 10-5 meter

ValueValue

5.605.60

5.65.6

0.0120.012

0.00120030.0012003

0.01200.0120

0.00120.0012

# of significant # of significant figuresfigures

33

22

22

55

33

22

If the digit immediately to the right of the last significant digit is less than 5, it is dropped 5 or greater - last significant digit

increased by 1 41.58 square meters 41.6 square

meters

Round 65.145 meters to 4 sig figs 65.15m

Round 100.1°C to 1 sig fig 100°C

Round 154 cm to 2 sig figs 150

Round 0.000718 kilograms to 2 sig figs 0.00072

Counting Example: 23 people in the classroom

▪ (Not 22.9 or 23.1) 23.00000000……………….

Exactly defined quantities Example: 60 minutes = 1 hour

▪ 60.00000000……………………..

calculated answer cannot be too precise not more precise than the least precise

measurement

Multiplication and Division same number of sig figs as the measurement

with the least number of sig figs

Addition and Subtraction same number of decimal places as the

measurement with the least number of decimal places

Accuracy How close a

measurement comes to the actual value of what is being measured

Precision How close a series

of measurements are to one another

Difference between accepted value and experimental value

error = experimental value – accepted value

% error = x 100% error

accepted value

% error = x 100%

99.1°C – 100.0°C x 100% 100.0°C

0.9°C x 100% 100.0°C

0.9%

error

accepted value

=

=

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