This question is about compounds - AQA - GCSE Chemistry - Question 5 - 2015 - Paper 2
Question 5
This question is about compounds.
Table 2 gives information about the solubility of some compounds.
Table 2
Soluble compounds
All potassium and sodium salts
All ... show full transcript
Worked Solution & Example Answer:This question is about compounds - AQA - GCSE Chemistry - Question 5 - 2015 - Paper 2
Step 1
Name a soluble compound that contains silver ions.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
A soluble compound that contains silver ions is silver nitrate, which can be represented chemically as AgNO₃.
Step 2
Name a soluble compound that contains carbonate ions.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
A soluble compound that contains carbonate ions is potassium carbonate, represented as K₂CO₃, or sodium carbonate, Na₂CO₃.
Step 3
What type of compound is a metal oxide?
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
A metal oxide is classified as a base, which is capable of reacting with acids to form salts.
Step 4
State how solid lead nitrate can be obtained from lead nitrate solution.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Solid lead nitrate can be obtained from lead nitrate solution by evaporating the water, which allows the solid to crystallize out as the solution cools.
Step 5
Balance the equation for the reaction.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The balanced equation for the reaction is:
ightarrow ext{Pb(NO}_3)_2 + ext{H}_2 ext{O}$$
Step 6
Give the total number of atoms in the formula Pb(NO3)2.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
In the formula Pb(NO₃)₂, there are a total of 9 atoms: 1 lead (Pb), 2 nitrogen (N), and 6 oxygen (O) atoms.
Step 7
Calculate the empirical formula of this lead oxide.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
To find the empirical formula, first determine the moles of each element:
Moles of lead: rac{6.21 ext{ g}}{207 ext{ g/mol}} = 0.03
Moles of oxygen: rac{0.72 ext{ g}}{16 ext{ g/mol}} = 0.045
Next, divide both by the smallest number of moles:
For lead: rac{0.03}{0.03} = 1
For oxygen: rac{0.045}{0.03} = 1.5
To obtain whole numbers, multiply by 2:
Lead: 2
Oxygen: 3
