UNIT 1 (Physical and Chemical Properties of Matter) HOMEWORK QUESTIONS

Write 57.0 in scientific notation.

5.7E1

Round to 3 significant figures: 57.048

57.0

Write 75.0 in scientific notation.

7.5E1

Write 0.00763 in scientific notation.

7.63E-3

Round to 3 significant figures: 0.0074983E4.

0.00750E4 or 75.0

Round to 3 significant figures: 0.0076321

0.00763

How many significant figures does 20miles have?

1

Write 12.2 in scientific notation.

1.22E1

Write 1760 in scientific notation.

1.760E3

Round to 3 significant figures: 12.17.

12.2

Round to 3 significant figures: 1764.9.

1760

How many significant figures does 0.0051g have?

2

How many significant figures does 0.010 have?

2

How many significant figures does 11m have?

2

How many significant figures does 22,000 have?

2

How many significant figures does 8.9E-2kg have?

2

How many significant figures does 0.00900L have?

3

How many significant figures does 90.4ºC have?

3

Sugar water is a (solid-solid/solid-liquid/gas-liquid/gas-gas).

solid-liquid

Carbon mixed with iron to form steel is a (solid-solid/solid-liquid/gas-liquid/gas-gas).

solid-solid

The term gas is limited to those substances that exist in the gaseous state at ordinary --- and ---.

temperatures, pressure

Gas (shape, volume, expansion, compressibility)

Indefinite, indefinite, great, great.

True/False: The properties of compounds are different from those of their component elements.

True (ex. carbon, hydrogen, and oxygen have totally different properties as a compound (sugar) than they do as individual elements)

What are some words that describe a physical change?

[Boil, freeze, melt, condense] reversible/[break, split, grind, cut, crush] irreversible.

How many phases exist in these types of mixtures? a. Homogenous b. Heterogenous

a. 1 b. 2 or more

Which of the following is NOT a state of matter? a. Water b. Gas c. Liquid d. Solid

a. Water

During a chemical reaction, the mass of products is always equal to the mass of ---.

reactants

In chemical reactants, the starting substances are called --- and the substances formed are called ---.

reactants, products

Which of the following is NOT a physical property? a. Odor b. Density c. Boiling point d. Corrosion

d. Corrosion

Can a compound be broken down to smaller components by physical means?

No, because they are chemically bound and must therefore be separated using chemical means.

Why are physical properties better used to separate mixtures than chemical properties?

Because it is easier and doesn't require an elaborate set-up.

What are some characteristics that indicate a chemical change is occurring?

Burn, corrode, rot.

Reversible Changes

Changes that result in a change of state.

What is a chemical property?

Characteristics of a material that become evident when that material undergoes a chemical change (ex. oxidation/rust, flammability).

Is adding HCl to Mg a physical or chemical change?

Chemical

Is burning paper a physical or chemical change?

Chemical

Write 98.5 in scientific notation.

9.85E1

Round to 3 significant figures: 98.473.

98.5

What happens in a chemical reaction?

A new substance is produced.

Accurate or precise: correct.

Accurate

Accurate or precise: single measurement.

Accurate

Accurate or precise: true value.

Accurate

Accurate or precise: 99 of 100 shots are made.

Accurate AND precise

What is used to represent each element?

Chemical symbol

Solid (shape, volume, expansion, compressibility)

Definite, definite, very slight, poor.

What are the two groups in which substances can be classified?

Element and compound

True/False: A heterogenous mixture is one that has a completely uniform composition.

False

True/False: All samples of a substance have different physical properties.

False

True/False: Elements can be separated easily into simpler substances.

False

True/False: It is always easy to separate the components in mixtures.

False

Liquid (shape, volume, expansion, compressibility)

Indefinite, definite, moderate, poor.

How can mixtures be separated?

Most use physical properties: boiling point differences, melting point differences, particle size, density, magnetism, solubility, color, smell (ex. separate aluminum and iron nail using magnetism).

Accurate or precise: 33 of 100 shots are made, rest miss.

Neither

Is dissolving NaCl a physical or chemical change?

Physical

Is grinding CuSo4 a physical or chemical change?

Physical

Is melting candle wax a physical or chemical change?

Physical

Is mixing NaCl and sand a physical or chemical change?

Physical

Is tearing Mg ribbon a physical or chemical change?

Physical

Is tearing paper a physical or chemical change?

Physical

Is heating CuSO4 a physical or chemical change?

Physical/Chemical

Accurate or precise: multiple measurements.

Precise

Accurate or precise: repeatable.

Precise

Accurate or precise: 99 of 100 shots hit the front of the rim, but bounce off.

Precise, but not accurate

Qualitative or quantitative observation: the flame is hot.

Qualitative

Qualitative or quantitative observation: a candle has a mass of 90g.

Quantitative

What is another name for a homogenous mixture?

Solution

What do boiling, melting, and freezing have in common?

They are all temperatures at which a change of state occurs and are all physical properties.

True/False: A chemist can help identify a substance by its physical properties.

True

True/False: Chemical properties are observed only when a substance undergoes a chemical change.

True

True/False: Most samples of matter are mixtures.

True

True/False: The elements that make-up a substance is always present in the same proportions.

True

True/False: The words gas and vapor can be used interchangeably.

True

Which of the following describes a part of a system with uniform composition and properties? a. Solution b. Mixture c. State d. Phase

d. Phase

Which of the following best completes this sentence?: A chemical change --- results in a change in chemical composition of the substances involved. a. Sometimes b. Rarely c. Always d. Never

c. Always

Compounds are substances that can be separated into simpler substances only by --- means.

chemical

A physical change alters a given material without changing its chemical ---.

composition

The subscript numbers in chemical formulas represent the proportions of the various elements in the ---.

compound

The law of conservation of mass states that in any physical change or chemical reaction, mass is neither --- nor ---.

created, destroyed.

Air is a (solid-solid/solid-liquid/gas-liquid/gas-gas).

gas-gas

Soda water is a (solid-solid/solid-liquid/gas-liquid/gas-gas).

gas-liquid