Appendix 1 measurements
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Appendix 1 - Measurements. We make QUALITATIVE observations of reactions — changes in color and physical state. We also make QUANTITATIVE MEASUREMENTS , which involve numbers . Use SI units —(International System of Units) based on the metric system. Standards of Measurement.

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Appendix 1 - Measurements

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Appendix 1 measurements

Appendix 1 - Measurements

  • We makeQUALITATIVEobservations of reactions — changes in color and physical state.

  • We also makeQUANTITATIVE MEASUREMENTS, which involve numbers.

    • UseSI units—(International System of Units) based on the metric system


Standards of measurement

Standards of Measurement

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

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


Some tools for measurement

Some Tools for Measurement

Which tool(s) would you use to measure:

A. temperature

B. volume

C. time

D. weight


Learning check

Learning Check

Match L) length M) mass V) volume

____ A. A bag of tomatoes is 4.6 kg.

____ B. A person is 2.0 m tall.

____ C. A medication contains 0.50 g Aspirin.

____ D. A bottle contains 1.5 L of water.

M

L

M

V


S i measurement

S.I. Measurement

Based on:

- number

- units

- accuracy report

S.I. Units are:

- related by factors of 10

* Table C of Reference Tables


Metric prefixes

Metric Prefixes

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3

  • Kilo- 10 or 1 kilometer = 10 m

    1 km or 1000 m

    10 m 1 km

  • Centi- 10 or 100 centimeters = 1 meter

    100 cm or 1 m

    1 m 100 cm

  • Milli- 10 or 1000 mm

    1 m

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Metric prefixes1

Metric Prefixes


Base units

Base Units

  • Length = meter (m)

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

Mass vs. Weight

Mass: Amount of Matter

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


Temperature

Temperature

  • Kelvin (K)

  • Measure of the average kinetic energy

    *Thermometer is a molecular speedometer. Shows vibrational energy.

  • Table T of

    Reference Tables


Appendix 1 measurements

Time

The base unit for time = seconds (s)

60 seconds = 1 minute = 1/60 hour


Amount of a substance

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

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

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

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?

  • Temperature change of 20.0 K for 200g water.

  • q= 4.18 J/gK X 200g X 20.0 K

  • q= 16,720 J or 16.7 KJ

    1 calorie = 4.18 Joules


Pressure

Pressure

  • Pascal (Pa)

  • Pa = force

    unit area

  • Table A of Reference Tables

  • 1 atm = 101.3 kPa


Density

Density

  • Table T of Reference Tables

  • Solve for m

    D X V = m

  • Solve for V = m

    D


Density practice

Density Practice

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

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

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

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