Moles
Acid, base and salt
Rate of reaction
Bonus Question
100

The ammonia formed reacts with nitrogen dioxide to form nitrogen and water. 

Balance the equation for this reaction. 

.....NO2+......NH3 → .....N2+12H2O

6, 8, 7

100

An insoluble salt is prepared by mixing solutions of silver nitrate and sodium chloride.

Write a chemical equation for the reaction occurring.

(AQA chemical past paper1)


AgNO3 + NaCl → AgCI +NaNO3

100

The iron in Fe2O3 is reduced by reaction with carbon monoxide. The unbalanced symbol equation is shown:

Complete the equation: 

Fe2O3 +__CO → __CO2 + __Fe

(2023 winter)

3,3,2

100

What is T.Daniel's favorite color?

Blue

200

135 moles of urea, (NH2)2CO, is stored in the tank of a car. 

Calculate the mass of the stored (NH2)2CO (in kg).

135 × 60 = 8100g 

and g to kg conversion = 8.1kg  

200

Zinc can be extracted by heating zinc oxide with carbon. The equation for the reaction is 

ZnO + C → Zn +CO

Explain which element is acting as a reducing agent in this reaction.

M1 carbon 

M2 it removes oxygen from the zinc (oxide) / causes zinc ions to gain electrons / gains oxygen / is oxidized

200

A student adds excess large pieces of magnesium carbonate, MgCO3, to dilute hydrochloric acid, HCl, and measures the volume of carbon dioxide gas, CO2, given off. 

Add the missing state symbols to the chemical equation for the reaction. 

MgCO3 .....+2HCl.....  →  MgCl2(aq)+H2O .....+CO2 .....

MgCO3(s) + 2HCl(aq) → MgCl2(aq) + H2O(l) + CO2(g)

300

Determine the volume of CO2 gas given off when excess MgCO3 is added to 25.0 cm3 of 0.400mol/ dm3 HCl at room temperature and pressure. 

MgCO3        +        2HCl →        MgCl2        +        H2O        +        CO2 

Use the following steps. 

● Calculate the number of moles of HCl in 25.0 cm3 of 0.400mol/ dm3 of acid. .............................. mol 

● Determine the number of moles of CO2 gas given off. .............................. mol 

● Calculate the volume of CO2 gas given off in cm3 . .............................. cm3

M1 mol HCl = 0.400 × 25.0 / 1000 = 0.01

M2 mol CO2 = M1 / 2 = 0.0100 / 2 = 0.005

M3 volume CO2 = M2 × 24000 = 120 (cm3)

300

Complete the following equation.

ZnCO3+ H2SO4 → .......+…….+…….

ZnCO3 + H2SO4 → ZnSO4+ CO2 + H2O

correct formula for zinc sulfate = 1

300

Write the ionic equation for the formation of lead(II) chloride by mixing aqueous solutions.

Include state symbols.

(2023 winter)

Pb2+(aq) + 2Cl-(aq) → PbCl2(s)


300

which planet is the furthest to us in solar system?

Neptune

400

Lead(II) sulfate is an insoluble salt. Lead(II) sulfate can be made from aqueous ammonium sulfate using a precipitation reaction. 

(i) Name a solution that can be added to aqueous ammonium sulfate to produce a precipitate of lead(II) sulfate. (1)

(ii) Write an ionic equation for this precipitation reaction. Include state symbols. (3)

(June 2023)

lead(II) nitrate 

(ii) Pb2+ (aq) +SO42-(aq) → PbSO4(s) 

M1 PbSO4 on the right

M2 only Pb2+ and SO42– on the left

M3 (aq) + (aq) → (s)

400

This question is about the insoluble salt lead(Il) bromide.

(a) A student uses the precipitation method to prepare lead (Il) bromide.The equation for the reaction she uses is 

Pb(NO3)(aq) + 2NaBr(aq) > PbBr2(S) + 2NaNO3 (aq)

Describe how she could use solutions of lead(II) nitrate and sodium bromide to obtain a pure, dry sample of lead (II) bromide.

(AQA chemical past paper2)

mix / add / react (the two) solutions / salts together stir filter wash (with water) suitable method of drying

identifying two suitable pieces of apparatus

400

Tetrachloromethane gas, CCl 4(g), reacts with steam as shown.

CCl 4(g) + 2H2O(g) CO2(g) + 4HCl(g)

The reaction is reversible. The forward reaction is exothermic.

(State what happens, if anything, to the rate of the forward reaction if the concentration of CCl4 is increased.

Explain your answer in terms of collision theory.

(2023 winter)

M1 rate of reaction increases

M2 more (CCl4) particles per unit volume

M3 frequency of collisions between (CCl4 and H2O) particles increases

500

Many organic compounds contain carbon, hydrogen and oxygen only. 

(a) An organic compound V has the following composition by mass. 

C, 48.65%; H, 8.11%; O, 43.24% 

Calculate the empirical formula of compound V. 

(b) Compound W has the empirical formula CH4O and a relative molecular mass of 32. 

Calculate the molecular formula of compound W. 

(June 2021)

(a)

M1 4.05 8.11 2.7

M2 1.5 : 3 : 1 OR 6 : 3 : 2 

M3 C3H6O2 

(b) (Mr of CH4O = 32) CH4O

500

Containers for fuel rods in nuclear reactors are made of zirconium.

Nuclear reactors are used to produce energy and to make radioactive isotopes.

(i) Which isotope of a different element is used as a fuel in nuclear reactors?


(ii) State one medical and one industrial use of radioactive isotopes 

 [1]

235U / 239Pu

NOTE: need symbol or name and nucleon number

[1]

[1]

[2]

(ii) treating cancer / chemotherapy / radiographs / tracer studies / x–ray (scans) /

sterilise surgical instruments / diagnose or treat thyroid disorders / radiotherapy

paper thickness / steel thickness / radiographs / welds / tracing / fill levels in

packages / food irradiation / smoke detectors

ACCEPT: any other uses

500

N2 + 3H2 ><(reversible) 2NH3

The forward reaction is exothermic. State the effect, if any, on the position of the equilibrium when the following changes are made. Explain your answers. temperature is reduced:

pressure is reduced:

(2022 winter)

Reduced Temperature:

M1 (position of) equilibrium moves to right-hand side 

M2 reaction is exothermic

Reduced pressure: 

M3 (position of) equilibrium moves to left-hand side

M4 more (gaseous) moles on left-hand side

500

Which chemist created the periodic table?

(2 for name, 2 for nationality, 1 for when)

The periodic table was invented by Russian chemist Dmitri Mendeleev in 1869.

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