Experimental Design

Question 1

What is the unit of mass?

Answer 1

g or kg

Question 2

What is the unit of time?

Answer 2

s

Question 3

What is the unit of temperature?

Answer 3

degrees celsius

Question 4

What is the unit of volume?

Answer 4

cm cube

Question 5

What is the physical quantity of g or kg?

Answer 5

mass

Question 6

What is the physical quantity of s?

Answer 6

time

Question 7

What is the physical quantity of degrees celsius?

Answer 7

temperature

Question 8

What is the physical quantity of cm cube?

Answer 8

volume

Question 9

What is the other unit for mass?

Answer 9

1 tonne = 1000 kg
1 mg = 10 to the power of -3 g

Question 10

What is the other unit for time that is used for scientific investigations?

Answer 10

NIL

Question 11

What is the other unit for temperature?

Answer 11

kelvin, 273.15 K = 0 degrees celsius

Question 12

What is the other unit for volume?

Answer 12

dm cube, 1 dm cube = 1000 cm cube

Question 13

A measurement should be recorded according to the __________________________.

Answer 13

A measurement should be recorded to the precision of the apparatus.

Question 14

Gas volumes may be measured using a _______________.

Answer 14

Gas volumes may be measured using a graduated gas syringe.

Question 15

Liquid volumes are often measured using a ____________, ___________ or ____________.

Answer 15

Liquid volumes are often measured using a measuring cylinder, burette or pipette.

Question 16

How do you read a meniscus reading?

Answer 16

For a concave meniscus, the correct volume will be read at the bottom of the curve. For a convex meniscus, the opposite is true and the correct reading will be at the top of the curve.

Question 17

The precision of the pipette is usually up to _____________ and that of the burette is up to ______________.

Answer 17

The precision of the pipette is usually up to 1 decimal place, and that of the burette is up to 2 decimal places (second d.p. is 0 or 5).

Question 18

Is it true that measuring cylinders may be of various precisions? Why or why not?

Answer 18

True.

This is because certain smallest division for cylinder are 0.1 ml, 0.5 ml or even 1 ml.

Question 19

Is a beaker meant to measure the volume of liquids? Why or why not?

Answer 19

A beaker is not to be used to measure volume of liquids. The markings on the side of a beaker are only approximate.

Question 20

The method of collecting a gas depends on its _________________ and _____________________.

Answer 20

The method of collecting a gas depends on its solubility in water and density relative to air.

Question 21

What are the three gas collection methods?

Answer 21

Displacement of water, downward delivery and upward delivery.

Question 22

Displacement of water is not suitable for ______________________________.

Answer 22

Displacement of water is not suitable for gases that dissolve or react with water. e.g. ammonia and sulfur dioxide.

Question 23

Downward delivery is suitable for __________________________.

Answer 23

Downward delivery is suitable for gases that are denser than air. e.g. chlorine

Question 24

Upward delivery is suitable for ________________________.

Answer 24

Upward delivery is suitable for gases that are less dense than air. e.g. hydrogen and ammonia.

Question 25

Often, the gas to be collected is contaminated with _______________. To dry the gas, pass the gas through a ________________. What are some examples?

Answer 25

Often, the gas to be collected is contaminated with water vapour. To dry the gas, pass the gas through a drying agent (also called dessicant).

Some examples are listed below:
- CONCENTRATED sulfuric acid (not suitable for alkaline gases, such as ammonia)— neutralisation will occur
- calcium oxide (not suitable for acidic gases)— e.g. HCl (hydrogen chloride), CO2, SO2
- anhydrous or fused calcium chloride (not suitable for ammonia)

Anhydrous copper (II) sulfate may be used as an indicator for water vapour,

It turns from white to blue in the presence of water.

Hydrogen chloride (gas) vs hydrochloric acid (aqueous solution