CIE iGCSE Co-Ordinated Science C3.1 Formulas Exam Style Questions Paper 1
Question
Pure substance X has a melting point of 110°C. The melting point ranges of four impure samples of substance X are measured. What is the melting point range of the most impure sample of substance X?
| Option | Melting Point Range (°C) |
|---|---|
| A | 81–85 |
| B | 86–92 |
| C | 98–99 |
| D | 102–110 |
▶️Answer/Explanation
Answer: A
Explanation: The most impure sample will have the widest and lowest melting point range, as impurities disrupt the crystal lattice, lowering and broadening the melting point.
Question
Propene, C3H6, burns in excess oxygen to form carbon dioxide and water.
wC3H6 + xO2 yCO2 + zH2O
Which values of w, x, y and z balance this equation?
▶️Answer/Explanation
Ans :C
Question
Which equation is balanced?
A 2H2 + O2 → 2H2O2
B MgO + 2H2SO4 → MgSO4 + 2H2O
C Na + H2O → NaOH + H2
D Na2CO3 + 2HCl → 2NaCl + H2O + CO2
▶️Answer/Explanation
Ans :A
Question
Propanol, CH3CH2CH2OH, burns in oxygen to produce carbon dioxide and water.
2CH3CH2CH2OH + 9O2 → xCO2 + yH2O
Which values of x and y balance the equation?
▶️Answer/Explanation
Ans 😀
Question
There are three times as many hydrogen atoms as carbon atoms in one molecule of hydrocarbon X.
What is the formula of X?
(A) CH$_{4}$
(B) C$_{2}$H$_{4}$
(C) C$_{2}$H$_{6}$
(D) C$_{2}$H$_{5}$OH
▶️Answer/Explanation
Ans: C
Question
Hydrogen reacts with oxygen to produce water.
What is the balanced equation for this reaction?
(A) H$_{2}$ + O$_{2}$ → H$_{2}$O
(B) H$_{2}$ + O$_{2}$ → 2H$_{2}$O
(C) H$_{2}$ + O → H$_{2}$O
(D) 2H$_{2}$ + O$_{2}$ → 2H$_{2}$O
▶️Answer/Explanation
Ans : D
Question
Potassium reacts with water.
potassium + water → ……1…… + ……2……
Which words complete the equation?
▶️Answer/Explanation
Ans : A
Question
When solid zinc carbonate is heated, a different solid and a gas are formed.
Which type of change occurs?
A chemical
B exothermic
C physical
D separation
▶️Answer/Explanation
Ans : A
Question
Dilute hydrochloric acid reacts with sodium carbonate to form sodium chloride, carbon dioxide and water.
The equation for the reaction is shown.
wHCl + Na$_{2}$CO$_{3}$ → xNaCl + yCO$_{2}$ + zH$_{2}$O
What are the values of w, x, y and z?
▶️Answer/Explanation
Ans: D
Question
Which equation represents the reaction between aluminium and oxygen?
(A) 2Al + 3O → Al$_{2}$O$_{3}$
(B) Al$_{2}$ + 3O → Al $_{2}$O$_{3}$
(C) 2Al $_{2}$ + 3O$_{2}$→ 2Al$_{2}$O$_{3}$
(D) 4Al + 3O$_{2}$ → 2Al $_{2}$O$_{3}$
▶️Answer/Explanation
Ans: D
Question
Which oxides of nitrogen have the same ratio of nitrogen atoms to oxygen atoms?
1. N2O
2. NO
3. NO2
4. N2O4
(A) 1 and 2 (B) 1 and 3 (C) 2 and 4 (D) 3 and 4
▶️Answer/Explanation
Ans: D