Appendix 1 - Appendix 1 - MeasurementsMeasurements

• We makeWe make QUALITATIVEQUALITATIVE observations of reactions — observations of reactions — changes in color and physical changes in color and physical state.state.

• We also makeWe also make QUANTITATIVE QUANTITATIVE MEASUREMENTSMEASUREMENTS, which involve , which involve numbersnumbers..

–UseUse SI unitsSI units —(International —(International System of Units) based on the System of Units) based on the metric systemmetric system

Standards of MeasurementStandards of Measurement

When we measure, we use a measuring tool to When we measure, we use a measuring tool to compare some dimension of an object to a standard.compare some dimension of an object to a standard.

For example, at one time the For example, at one time the standard for length was the standard for length was the king’s foot. What are some king’s foot. What are some

problems with this standard?problems with this standard?

Some Tools for Some Tools for MeasurementMeasurement

Which tool(s) Which tool(s) would you use to would you use to measure:measure:

A.A. temperature temperature

B.B. volume volume

C.C. time time

D.D. weight weight

Learning Check

Match Match L) lengthL) length M) mass M) mass V) volume V) volume

____ A. A bag of tomatoes is 4.6 kg.____ A. A bag of tomatoes is 4.6 kg.

____ B. A person is 2.0 m tall.____ B. A person is 2.0 m tall.

____ C. A medication contains 0.50 g Aspirin.____ C. A medication contains 0.50 g Aspirin.

____ D. A bottle contains 1.5 L of water.____ D. A bottle contains 1.5 L of water.

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M

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S.I. MeasurementS.I. Measurement

Based on:Based on:

- number- number

- units- units

- accuracy report- accuracy report

S.I. Units are:S.I. Units are:

- related by factors of 10- related by factors of 10

* Table C of Reference Tables* Table C of Reference Tables

Metric PrefixesMetric Prefixes• Kilo-Kilo- 10 or 1 kilometer = 10 m 10 or 1 kilometer = 10 m

1 km or 1000 m1 km or 1000 m

10 m 1 km10 m 1 km

• Centi-Centi- 10 or 100 centimeters = 1 meter 10 or 100 centimeters = 1 meter

100 cm or 1 m100 cm or 1 m

1 m1 m 100 cm 100 cm

• Milli-Milli- 10 or 1000 mm 10 or 1000 mm

1 m1 m

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Metric PrefixesMetric Prefixes

Base UnitsBase Units• Length = meter (m)Length = meter (m)

• Mass = kilogram (kg) also gram (g)Mass = kilogram (kg) also gram (g)

Mass vs. WeightMass vs. Weight

Mass: Mass: Amount of MatterAmount of Matter

Weight: Weight: Force exerted by Force exerted by the mass, only present the mass, only present

with gravitywith gravity

Temperature

• Kelvin (K)Kelvin (K)

• Measure of the average Measure of the average kinetic energykinetic energy

*Thermometer is a *Thermometer is a molecular speedometer. molecular speedometer.

Shows vibrational Shows vibrational energy.energy.

• Table T ofTable T of

Reference TablesReference Tables

Time

The base unit for time = seconds (s)

60 seconds = 1 minute = 1/60 hour

Amount of a Substance

• Measured in moles (mol)

• Contains Avogadro’s number of particles

• 6.02 X 10

• 602,000,000,000,000,000,000,000

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Derived Units - Volume

• Liter (L)

• Volume = L X W X H

• 1cm X 1cm X 1cm = cm or 1ml

• 1dm X 1dm X 1dm = dm or 1L

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Derived Units – Heat Energy

• Joules (J)

• 4.18 J = the energy needed to raise the temperature of 1 gram of water 1 degree K.

• Table B of Reference Tables – Specific Heat of Water

Heat (q) = 4.18J/gK X g (water) X t

Heat Energy

• Suppose that a calorimeter contains 200. grams of water at 294.0 K. As an exothermic reaction occurs the water temperature rises to 314.0 K.

• What is the quantity of heat transferred?

1.Temperature change of 20.0 K for 200g water.

2.q= 4.18 J/gK X 200g X 20.0 K

3.q= 16,720 J or 16.7 KJ

1 calorie = 4.18 Joules

Pressure

• Pascal (Pa)

• Pa = force

unit area

• Table A of Reference Tables

• 1 atm = 101.3 kPa

Density

• Table T of Reference Tables

• Solve for m

D X V = m

• Solve for V = m

D

Density Practice

1. What is the density of an object with a mass of 20.1g and a volume of 142.5cm ?

1. What is the mass of an object with a density of 32.1 g/cm and a volume of 10.0cm ?

2. What is the volume of an object with a mass of 40g and a density of 10g/cm ?

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