Chemical Analysis

Question 1

When a test for carbon dioxide is positive, limewater looks __________ .

Answer 1

cloudy

Question 2

The chemical test for chlorine is that it bleaches moist __________ paper.

Answer 2

litmus

Question 3

Which gas would you test for with a glowing splint?

Answer 3

oxygen

Question 4

When an unknown gas was bubbled through lime water, it went cloudy. Name the gas.

Answer 4

carbon dioxide

Question 5

Name the liquid that can be used to test for carbon dioxide.

Answer 5

limewater

Question 6

Which gas would you test for with a lighted splint?

Answer 6

hydrogen

Question 7

Name the substance that limewater is used to test for.

Answer 7

carbon dioxide

Question 8

Which gas would you test for with limewater?

Answer 8

carbon dioxide

Question 9

What is the common name for calcium hydroxide dissolved in water?

Answer 9

limewater

Question 10

What is not an example of a formulation?

Answer 10

salt

Question 11

Cleaning agents are complex mixtures of chemical components, each with its own specific purpose. The components have very precise measurements to ensure that the cleaning agent has the right properties. What is a cleaning agent an example of?

Answer 11

formulation

Question 12

The Rf value was calculated to be 0.7 for a pigment spot that had travelled 14 cm on a chromatogram. What distance had the solvent front travelled?

Answer 12

20cm

Question 13

A carton of apple juice has “pure apple juice” printed on it. Does this mean that the apple juice contains only one type of chemical compound?

Answer 13

no

Question 14

True or false? We can use the melting and boiling point of a substance to identify it.

Answer 14

true

Question 15

What is the missing word? In paper chromatography, the solvent used is known as the __________ phase.

Answer 15

mobile

Question 16

True or false? Pure substances always consist of single elements only.

Answer 16

false

Question 17

What is the scientific term for a liquid that dissolves substances?

Answer 17

solvent

Question 18

A formulation is a __________ that has been designed as a useful product.

Answer 18

mixture

Question 19

The distance travelled by a pigment spot in a chromatogram was found to be 5 cm. The distance travelled by the solvent front was found to be 10 cm. What is the pigment’s Rf value?

Answer 19

0.5

Question 20

In paper chromatography, the paper itself is known as the __________ phase.

Answer 20

stationary

Question 21

True or false? A pure substance has a sharp melting and boiling point.

Answer 21

true

Question 22

Rikki has a sample of water but he is not sure if it is pure or not. He heats the water until it begins to boil. He records the temperature which is 103°C. Is this water pure?

Answer 22

no

Question 23

True or false? Impurities in a chemical lead to changes in the melting and boiling point of the chemical.

Answer 23

true

Question 24

True or false? A compound can have different Rf values in different solvents.

Answer 24

true

Question 25

In chemistry, a substance is __________ if it is a single element or compound that is not mixed with any other substance.

Answer 25

pure

Question 26

pure substance

Answer 26

• only contains one compound or element throughout
• not mixed with anything else

Question 27

mobile phase

Answer 27

where molecules can move (liquid or gas)

Question 28

stationary phase

Answer 28

where molecules can’t move (solid or really thick liquid)

Question 29

chromatography

Answer 29

method used to separate substances in a mixture