Working With Gases In The lab

Question 1

What is used to drop DLIUTE ACID?

Answer 1

THISTLE FUNNEL

Question 2

What is used to drop CONCENTRATED ACID?

Answer 2

DROPPING FUNNEL

Question 3

Give an example of a reaction to produce CO2 gas. Mention the apparatus used and the reactants and products.

Answer 3

Step 1: Measure (weight) a certain amount CaCO3 (marble chips=solid) and place it in a flask.

Step 2: Add dilute HCL (acid= aq).

Step 3: Measure the amount of gas collected using a gas syringe.

REACTION:

CaCO3 (s) + 2HCl (aq) -> CaCl2 (aq) + H2O (l) + CO2 (g)

Question 4

Give an example of a reaction to produce H2 gas. Mention the apparatus used and the reactants and products.

Answer 4

Step 1: Measure (weight) a certain amount of pieces of Zn (solid) and place it in a flask.

Step 2: Add dilute HCL (acid= aq).

Step 3: Measure the amount of gas collected using a gas syringe.

REACTION:

Zn (s) + 2HCl (aq) -> ZnCl2 (aq) + H2 (g)

Question 5

Give an example of a reaction to produce O2 gas. Mention the apparatus used and the reactants and products.

Answer 5

Step 1: Measure (weight) a certain amount of Manganese (IV) Oxide (used as a catalyst) and place it in a flask.

Step 2: Add H2O2.

Step 3: Measure the amount of gas collected using a gas syringe.

REACTION:
2 H2O2(aq) -> 2 H2O (l) + O2 (g)

Question 6

How do you obtain Ammonia (NH3)?

Answer 6

Heat any AMMONIUM compound with a BASE, both reactant should be in solid form. Ex. Base such as NaOH or CaOH
Ex. Ammonium compound such as NH4+

Question 7

What is a GAS JAR used for?

Answer 7

To COLLECT gas over water.

Question 8

***How do you use a measuring cylinder to measure the volume of a GAS?

Answer 8

Use a measuring cylinder over water to collect the gas over it.
(NOTE: NOT ACCURATE)

Question 9

How do you measure the volume of a gas accurately?

Answer 9

By using a GAS SYRINGE.

Question 10

What method of collecting a gas do you use when the gas is HEAVIER the air?

Answer 10

Upward displacement of air

The GAS JAR is placed with its opening upwards since the gas is heavy so it collects.

(see pg 278)

Question 11

What method is used to collect gas when the gas is lighter than air.

Answer 11

Downward displacement of air

The GAS JAR is facING DOWNWARDS since the gas is light and will collect at the base of the gas jar which is upside down to hold the gas.

(See pg 278)

Question 12

What method do use to collect a gas that is SPARINGLY SOLUBLE in water?

Answer 12

Over water

The gas dissolved in the Water for a while.

(See pg 278)

Question 13

What is the test for Ammonia, NH3?

Answer 13

Test = Hold a damp red litmus paper in it.
Result = Indicator paper turns BLUE. (Since its alkaline) 

Properties = Colourless, ALKALINE, Gas, Strong sharp smell

Question 14

What is the test for Carbon Dioxide, CO2?

Answer 14

Test = Bubble the gas through lime water
Result = Limewater turns CLOUDY / MILKY

Properties = Colourless, Weakly acidic, Gas, Reats with limewater (aq sol. Of CaOH) to give a white PRECIPITATE of CaCO3

Question 15

What is the test for Chlorine gas, Cl2?

Answer 15

Test = Hold a damp indicator paper in the gas which is in a fume cupboard.
Result = Indicator turns WHITE

Properties = Green, Poisonous, Gas, BLEACHES Dyes

Question 16

What is the test for Hydrogen gas, H2?

Answer 16

Test = Collect gas in a tube and hold a lighted splint to it.
Result = The gas burns with a SQUEAKY POP

Properties = Colourless, Gas, COMBINES violently with O2 when lit.

Question 17

What is the test for Oxygen, O2?

Answer 17

Test = collect gas in a test tube and hold a GLOWING SPLINT to it.
Result = The splint immediately bursts into a FLAME

Properties = Colourless, FUELS BURN much more easily in it than in air

Question 18

What is the test for suffer dioxide, SO2?

Answer 18

Test = Soak a piece of filter paper in an acidified (which means a little dilute acid (ex. HCO acid (aq)) has been added) Potassium Manganese (VII). Place it in the gas.
Result = The colour of the gas changes from PURPLE TO COLOURLESS

Properties = Colourless, poisonous, acidic gas, Choking smell, REDUCES PURPLE potassium manganese (VII) ion to COLOURLESS potassium manganese(II) ion

I.e from (VII) -> (II)