Rusting of Iron - Investigation Result

Rusting of Iron - Investigation Result

rusting   11:15

Rustiong of Iron Investigation

Rustiong of Iron Investigation

rusting   11:06

Rusting Investigation

Collect the following: -

• 5 test tubes

• 1 beaker

• Cotton wall

• 1 painted iron nail

• 4 normal nails

• 6 labels

Carry out the following five experiments – make sure you label each test tube, and label the beaker with all your test tubes in with your group name

Experiment 1

Place the painted nail in a test tube and totally cover with water – label this painted nail + water

Experiment 2

Put a plain nail in a test tube and ½ cover this with water – label this control

Experiment 3

Cover a plain nail in Vaseline (using a paper towel) and totally cover with water – label this greased nail

Experiment 4

Add some calcium chloride crystals in a test tube, and add a little cotton wool in the top of the test tube, pushing it down with a spatula so that it is just above the crystals. Add a plain nail on top of the cotton wool, and place some more cotton wool in the top of the test tube – label this calcium chloride

Experiment 5

Put a plain nail in a test tube and totally cover this with boiled water. Add a little oil on top of the water, and bung the test tube – label this oil

Rusting of Iron Quiz (answered)

Rusting of Iron Quiz (answered)

rusting   13:40

Name/# /ClASS      : MARKS:

DAY, DATE :

Answer the following questions briefly on your “kertas ulangan”, then fasten the question sheet and the answer sheet securely together. You are not allowed to use any correction tools. There are 40 marks possibly.  Define the meaning of :  “corrosion”  and  “rusting”, what are the differences the both terms.   [4 marks] Why  the rusting of iron is called a slow reaction [3 mark]

2. Write chemical equiation for:

1. the oxidation of iron atoms to iron(II) ions. [2 marks]

Fe(s) 🡪 Fe2+(aq)    +    2e-

2. the reduction of oxygen in the presence of water to form hydroxide ions. [2 marks]

O2(g)   +   2H2O(l)   +   4e-      🡪     4OH-(aq)

3. Suggest why no corrosion has occurred in tube 2. [3 marks]

keyword: free moisture/dry air

4. Suggest why no corrosion has occurred in tube 3. [3 marks]

Keyword: boiled water—free O2; preventing by oil layer

5. Suggest why there is more corrosion in tube 4 than in tube 1. [3 marks] keyword: compare the oxygen content of the both tube.

6. Suggest why corrosion of an iron object is reduced (or stopped) in each of the following situations.

1. Outer space [2 marks] keyword: no oxygen

2. At the bottom of the ocean. [2 marks] keyword: limited/lack of oxygen

3. When the object is coated with oil. [2 marks] keyword: oil prevent O2 and H2O away from the metals

7. Metal rubbish bins are often coated with zinc. Metal food containers are coated with tin.

1. Why the zinc coating on rubbish bins protects the iron from corrosion. [3 marks] keyword: reactivity

2. Why is a zinc coating not suitable for use on food containers? [3 marks] keyword: rust; healthy

8. Complete this table showing whether there is rusting or not, and if it occurs, whether the corrosion is slow, fast or very fast. [4 marks]

Speed of corrosion	Water	Air	Salt
a.	√	x	x
b.	x	√	x
c.	√	√	x
d.	√	√	√

Keyword: rust : the present of O2 and water

9. Why does iron corrode faster/very fast in previous questions (no. 8) [2 marks] keyword: catalyst

Why are pieces of household equipment packed in cartons with a sachet of silica gel? [2 marks] keyword: drying agent; good maintenan