Experiments: Section 5

Question 1

Equiptment: The Rusting Experiment

(5 things)

Answer 1

. Nail
. Three test tubes
. Water
. Oil
. Kettle

Question 2

The rusting experiment

(Method)

Answer 2

1st tube nail in oxygen and water
2nd tube nail in boiled water but oil on top for no oxygen
3rd tube nail in oxygen but no water

The nail only rusts inn the 1st tube.

Question 3

Equiptment: Acid-alkali Titrations

(6 things)

Answer 3

. Burette
. Clamp
. Clamp stand
. White tile
. Volumetric pipette
. Conical flask

Question 4

Acid-alkali titrations

(method)

Answer 4

Use the pipette to place 25 cm3 sodium hydroxide solution into the conical flask
Place the conical flask on a white tile so the tip of the burette is inside the flask
Add a few drops of a suitable indicator to the solution in the conical flask
Perform a rough titration by taking the burette reading and running in the solution in 1 – 3 cm3 portions, while swirling the flask vigorously
Quickly close the tap when the end-point is reached (sharp colour change)
Then record the volume, on the meniscus
Now repeat the titration with a fresh batch of sodium hydroxide
As the rough end-point volume is approached, add the solution from the burette one drop at a time until the indicator just changes colour
Record the volume to the nearest 0.05 cm3
Repeat until you achieve two concordant results to increase accuracy

Question 5

What is a meniscus?

Answer 5

The curved upper surface of a liquid in a tube.

Question 6

What are concordant results?

Answer 6

Two results that are within 0.1 cm3 of each other.