Consider supporting us on Patreon. Help us keep revisedeck free.
6. Chemical reactions
A section of Chemistry, 5070
Listing 10 of 377 questions
A scientist investigates the thermal decomposition of calcium carbonate in a closed system. A dynamic equilibrium mixture is established. CaCO3CaO+ CO2What is meant by the term dynamic equilibrium? The pressure of the equilibrium mixture is decreased. The temperature of the closed system is kept constant. Predict and explain what will happen to the composition of the equilibrium mixture. The temperature of the equilibrium mixture is increased. The pressure within the closed system is kept constant. The position of equilibrium shifts to the right hand side. What conclusion can be made about the enthalpy change of the reaction? Calcium carbonate reacts with dilute nitric acid to form three compounds, X, Y and Z. • X is a salt. • Y is a colourless gas. • Z is a colourless liquid. Name Y and describe a test for this gas. name test observation Name Z and describe a chemical test for this liquid. name chemical test observation Construct the equation for the reaction between calcium carbonate and nitric acid.
5070_s18_qp_22
THEORY
2018
Paper 2, Variant 2
View
A scientist heats a sample of phosphorus(chloride in a closed container. A dynamic equilibrium is established. PCl 5PCl 3+ Cl 2Describe what is meant by the term dynamic equilibrium. The pressure of the equilibrium mixture is increased. The temperature of the equilibrium mixture is kept constant. Predict and explain what will happen, if anything, to the composition of the equilibrium mixture. prediction explanation The temperature of the equilibrium mixture is increased. The pressure of the equilibrium mixture is kept constant. Suggest why the position of equilibrium moves to the right. Explain why the rate of the reaction increases. Draw the ‘dot-and-cross’ diagram for a molecule of PCl 3. Only include the outer shell electrons. PCl 5 reacts with water to form hydrogen chloride and phosphoric acid, H3PO4. Construct an equation for this reaction.
5070_s19_qp_21
THEORY
2019
Paper 2, Variant 1
View
The rate of reaction between calcium carbonate and hydrochloric acid is measured in three separate experiments. dilute hydrochloric acid mass balance 2 g calcium carbonate cotton wool In experiment 1, the calcium carbonate is powdered and an excess of hydrochloric acid is used. In experiment 2, the calcium carbonate is in lumps and an excess of hydrochloric acid is used. In experiment 3, the calcium carbonate is in lumps but insufficient hydrochloric acid is used. The results of these experiments are shown...
5070_s20_qp_11
MCQ
2020
Paper 1, Variant 1
View
Aqueous ammonium nitrite, NH4NO2, decomposes when heated, as shown. NH4NO2N2+ 2H2OA 25.0 cm3 sample of 0.150 mol / dm3 NH4NO2is heated. Calculate the maximum volume, in dm3, of nitrogen formed, measured at room temperature and pressure. volume of nitrogen dm3 The concentration of NH4NO2is decreased. The temperature of the reaction remains constant. State and explain how the rate of reaction changes. NH4NO2 contains the ammonium ion, NH4 +, and the nitrite ion. A mixture of aqueous calcium hydroxide and NH4NO2is warmed. Calcium nitrite, water and a gas are formed. The gas turns damp red litmus paper blue. Construct the equation for this reaction. NH4NO2is added to a sample of aqueous potassium iodide. A brown solution is formed. Name the brown solution. Name the type of reaction that causes this brown solution to form.
5070_s21_qp_21
THEORY
2021
Paper 2, Variant 1
View
Sulfamic acid, NH2SO3H, is a white crystalline solid. It reacts with aqueous sodium nitrite to make nitrogen gas, as shown in the equation. NH2SO3H+ NaNO2N2+ H2O+ NaHSO4An excess of sulfamic acid reacts with a 20.0 cm3 sample of 0.150 mol / dm3 NaNO2. Calculate the maximum volume, in dm3, of nitrogen formed, measured at room temperature and pressure. volume of nitrogen dm3 The rate of this reaction can be determined by measuring the volume of nitrogen formed every second. Draw a labelled diagram of the assembled apparatus that can be used to make, collect and measure the volume of nitrogen formed in this reaction. The concentration of NaNO2is increased. The temperature of the reaction remains constant. State and explain how the rate of reaction changes. Sulfamic acid forms salts called sulfamates that contain the anion NH2SO3 −. Magnesium carbonate, MgCO3, is added to a sample of NH2SO3H. Magnesium sulfamate, water and a gas are formed. The gas turns limewater milky. Construct the equation for this reaction.
5070_s21_qp_22
THEORY
2021
Paper 2, Variant 2
View
Questions Discovered
377