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## Classification of matter

Exercise 2.4

Which of the following can be classified as a mixture:

1. sugar

2. table salt

3. air

4. iron

Solution not yet available.

An element can be defined as:

1. A substance that cannot be separated into two or more substances by ordinary chemical (or physical) means

2. A substance with constant composition

3. A substance that contains two or more substances, in definite proportion by weight

4. A uniform substance

Solution not yet available.

Classify each of the following substances as an element, a compound, a homogeneous mixture, or a heterogeneous mixture: salt, pure water, soil, salt water, pure air, carbon dioxide, gold and bronze.

Solution not yet available.

Look at the table below. In the first column (A) is a list of substances. In the second column (B) is a description of the group that each of these substances belongs in. Match up the substance in Column A with the description in Column B.

 Column A Column B 1. iron A. a compound containing 2 elements 2. $$\text{H}_{2}\text{S}$$ B. a heterogeneous mixture 3. sugar solution C. a metal alloy 4. sand and stones D. an element 5. steel E. a homogeneous mixture
Solution not yet available.

You are given a test tube that contains a mixture of iron filings and sulfur. You are asked to weigh the amount of iron in the sample.

1. Suggest one method that you could use to separate the iron filings from the sulfur.

2. What property of metals allows you to do this?

Solution not yet available.

Given the following descriptions, write the chemical formula for each of the following substances:

1. silver metal

2. a compound that contains only potassium and bromine

3. a gas that contains the elements carbon and oxygen in a ratio of $$\text{1}$$:$$\text{2}$$

Solution not yet available.

Give the names of each of the following compounds:

1. $$\text{NaBr}$$

2. $$\text{Ba}(\text{NO}_{2})_{2}$$

3. $$\text{SO}_{2}$$

4. $$\text{H}_{2}\text{SO}_{4}$$

Solution not yet available.

Give the formula for each of the following compounds:

1. iron (II) sulfate

2. boron trifluoride

3. potassium permanganate

4. zinc chloride

Solution not yet available.

For each of the following materials, say what properties of the material make it important in carrying out its particular function.