Chlorine and Cu Zn
1
a) Which element on the table
i) is an alkali metal? Li, Na, K ii) can be cut with a knife? K, Na, Li
b) Arrange the elements Li, Na and K in terms
i) Hardness starting from the softest. K, Na, Li ii) Melting point starting from the least K, Na, Li
iii) Density starting from the least. K, Na, Li iv) Reactivity starting from the least reactive. Li, Na, K
c) A piece of sodium was dropped in a trough containing water.
i) Describe what you would see.
Sodium melts almost at once to form a small ball that dashes around the surface. . If the sodium becomes trapped on the side of the container, the hydrogen may catch fire to burn with an orange flame ii) Write a word and symbol equation for the reaction. sodium + water → sodium hydroxide + hydrogen
2Na + 2H2O → 2NaOH + H2 iii) what would be the effect of the solution formed on litmus paper
The solution is an alkali and so turns red litmus paper blue and red litmus paper turns red.
f) Which metals on the table i) form coloured compounds? Fe, Cu Zn ii) have catalytic ability? Fe, Cu Zn iii) show multiple valencies? C iv) are hard? Fe, Cu Zn v) are highly reactive? Li, Na. K, F, Cl, Br
2. (a) Which of the two metals lithium or rubidium
(i) is harder? Lithium
(ii) has a higher density? Lithium
(iii) has a lower melting point? Rubidium (b) How are these metals stored and what is the reason for it?
They are stored in oil to prevent them from reacting with the moisture in the air and oxygen.
3. A 26.5g sample of impure paracetamol contains 24.5g of pure paracetamol. Calculate the % purity of this paracetamol.
%purity = pure/impure x 100 = 24.5/26.5 x 100 = 92.5% 4. When 11.50g of sodium reacts with excess chlorine, 22.3g of sodium chloride is made.
2Na + Cl2 2NaCl
Ar : Na = 23, Cl = 35.5
Calculate:
a.
a) Which element on the table
i) is an alkali metal? Li, Na, K ii) can be cut with a knife? K, Na, Li
b) Arrange the elements Li, Na and K in terms
i) Hardness starting from the softest. K, Na, Li ii) Melting point starting from the least K, Na, Li
iii) Density starting from the least. K, Na, Li iv) Reactivity starting from the least reactive. Li, Na, K
c) A piece of sodium was dropped in a trough containing water.
i) Describe what you would see.
Sodium melts almost at once to form a small ball that dashes around the surface. . If the sodium becomes trapped on the side of the container, the hydrogen may catch fire to burn with an orange flame ii) Write a word and symbol equation for the reaction. sodium + water → sodium hydroxide + hydrogen
2Na + 2H2O → 2NaOH + H2 iii) what would be the effect of the solution formed on litmus paper
The solution is an alkali and so turns red litmus paper blue and red litmus paper turns red.
f) Which metals on the table i) form coloured compounds? Fe, Cu Zn ii) have catalytic ability? Fe, Cu Zn iii) show multiple valencies? C iv) are hard? Fe, Cu Zn v) are highly reactive? Li, Na. K, F, Cl, Br
2. (a) Which of the two metals lithium or rubidium
(i) is harder? Lithium
(ii) has a higher density? Lithium
(iii) has a lower melting point? Rubidium (b) How are these metals stored and what is the reason for it?
They are stored in oil to prevent them from reacting with the moisture in the air and oxygen.
3. A 26.5g sample of impure paracetamol contains 24.5g of pure paracetamol. Calculate the % purity of this paracetamol.
%purity = pure/impure x 100 = 24.5/26.5 x 100 = 92.5% 4. When 11.50g of sodium reacts with excess chlorine, 22.3g of sodium chloride is made.
2Na + Cl2 2NaCl
Ar : Na = 23, Cl = 35.5
Calculate:
a.