Chemistry Chapter: Matter and Measurement

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Questions and Answers

Which molecule consists of one carbon atom and two oxygen atoms?

Methane

Ammonia

Ozone

Carbon dioxide (correct)

What aspect of substances do chemists study to predict their behavior?

The physical state of matter

Knowledge of physical and chemical properties (correct)

The appearance and color of compounds

Chemical reactions of substances

Which of the following is NOT an example of a chemical property?

Melting point (correct)

Combustibility

Basicity

Acidity

Quantitative measurement of physical properties is required for which of the following?

Scientific investigation Signup and view all the answers

What does a water molecule consist of?

Two hydrogen atoms and one oxygen atom Signup and view all the answers

Which property is considered a characteristic reaction of different substances?

Chemical reactivity Signup and view all the answers

Which of the following is essential for the accurate measurement of physical properties?

National Standards of Measurement Signup and view all the answers

What type of properties include length, area, and volume?

Quantitative properties Signup and view all the answers

What is the fixed numerical value of the Boltzmann constant when expressed in units of JK–1?

1.380649×10–23 Signup and view all the answers

How many elementary entities are contained in one mole?

6.02214076×10^23 Signup and view all the answers

What symbol is used to represent the amount of substance in the SI unit system?

n Signup and view all the answers

What is the SI unit of luminous intensity?

candela Signup and view all the answers

What is the fixed numerical value of the luminous efficacy of monochromatic radiation of frequency 540×10^12 Hz?

683 Signup and view all the answers

An elementary entity can be any of the following EXCEPT:

a liter Signup and view all the answers

Which of the following statements correctly describes the kilogram, metre, and second in SI units?

They are defined in terms of h, c, and ΔV Cs. Signup and view all the answers

What does the unit 'lm·W–1' represent?

Luminous efficacy Signup and view all the answers

How many significant figures are represented in the number 100?

3 Signup and view all the answers

What is the correct scientific notation for the number 100 with two significant figures?

1.0×10^2 Signup and view all the answers

Which of the following has four significant figures?

9.4213g Signup and view all the answers

When counting objects, how are significant figures treated?

They have infinite significant figures. Signup and view all the answers

If you multiply 3.56 (3 significant figures) by 2.1 (2 significant figures), how many significant figures should the result have?

2 Signup and view all the answers

What is the significant figure count for the number 18.0?

2 Signup and view all the answers

In scientific notation, how many significant figures are in the number 4.01×10^2?

3 Signup and view all the answers

How should the result of a measurement that is 31.1 be reported when it has one digit after the decimal point?

31.1 Signup and view all the answers

Which statement accurately describes the system of atomic masses?

It uses carbon-12 as the standard established in 1961. Signup and view all the answers

What does one atomic mass unit (amu) represent?

The mass equal to one-twelfth of a carbon-12 atom. Signup and view all the answers

How is molecular mass calculated?

By summing atomic masses multiplied by the number of atoms of each element. Signup and view all the answers

Which of the following is NOT a principle of atomic theory as proposed?

All atoms of a given element have different properties. Signup and view all the answers

In the atomic mass system, what is assigned the mass of exactly 12 amu?

Carbon-12 atom. Signup and view all the answers

What can be deduced about the mass of the hydrogen atom?

Its mass is expressed in atomic mass units and has been provided as 1.6736×10–24 g. Signup and view all the answers

Which of the following statements about elements and compounds is true?

Compounds are formed when atoms of different elements combine in a fixed ratio. Signup and view all the answers

Which of the following statements is a fundamental premise of atomic theory?

Chemical reactions involve the rearrangement of atoms. Signup and view all the answers

What is the purpose of a unit factor in conversions?

To maintain the value while changing units Signup and view all the answers

How many inches are equivalent to 2.54 cm?

1 in Signup and view all the answers

If 1 day is equal to 24 hours, how many hours are there in 5 days?

120 hours Signup and view all the answers

What is the total number of minutes in 2 hours and 30 minutes?

150 minutes Signup and view all the answers

Using the unit factors, how many seconds are in 2 days?

172800 seconds Signup and view all the answers

What is the result of multiplying 1 by a unit factor?

It remains unchanged Signup and view all the answers

If 1 hour equals 60 minutes, how many minutes are there in 3 hours?

180 minutes Signup and view all the answers

How is the unit factor derived from the equivalence of inches to centimeters?

By setting the ratio equal to 1 Signup and view all the answers

Study Notes

Describing Matter

Physical properties are characteristics which can be observed without changing the chemical composition of the substance.
Chemical properties are characteristics of a substance that describe how it reacts with other substances.
The atoms of different elements have different masses.
Compounds are formed when atoms of different elements combine in a fixed ratio.
Chemical reactions involve the reorganisation of atoms.
Molecules are formed when two or more atoms combine.
Water (H2O) and carbon dioxide (CO2) are examples of compounds.

Measuring Matter

Quantitative measurement of properties is required for scientific investigation.
Unit definitions change over time to improve measurement accuracy.
The International System of Units (SI) is the most widely used system of units.
Accurate measurements are essential for scientific research and development.

The Measurement of Physical Properties

Quantitative properties can be measured and expressed numerically.
Accurate measurement is crucial in all scientific fields.
Uncertainty is inherent in all measurements and depends on the instrument used and the skill of the person making the measurement.

Maintaining National Standards of Measurement

The present system of atomic masses is based on carbon-12 as the standard.
One atomic mass unit (amu) is defined as 1/12 the mass of one carbon-12 atom.
Avogadro's number is 6.022 x 10^23, the number of atoms, molecules, or other particles in one mole of a substance.

Significant Figures

Significant figures indicate the precision of a measurement.
The number of significant figures in a result should be the same as the number of significant figures in the least precise measurement used.
Scientific notation uses exponents to represent very large or very small numbers.
Significant figures in scientific notation include all the digits in the coefficient.

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Description

Explore the fundamental concepts of matter, its physical and chemical properties, and the importance of accurate measurement in scientific investigation. This quiz covers topics including atoms, compounds, and the International System of Units (SI). Test your knowledge and understanding of these essential chemistry principles.