Exam code: 4XSD1
This question is about the reaction between sodium and water.
Which statement about this reaction is correct?
Sodium sinks to the bottom of the water
A lilac flame is seen
A solution of sodium oxide is produced
Bubbles of hydrogen gas are produced
Was this exam question helpful?
Which of the following could not be predicted about caesium, based on the trends seen in Group 1 metals?
It is soft
It has a relatively high melting point
It is very reactive
It has a relatively low density
Was this exam question helpful?
A teacher adds a small piece of potassium to a large trough of water to form a solution.
When the reaction has completed she adds a few drops of universal indicator to the solution.
What is the most likely pH value of the solution?
3
7
8
12
Was this exam question helpful?
This question is about some of the Group 1 elements and their compounds.
A teacher adds a small piece of lithium to water in a trough.
i) Give three observations that are made when lithium reacts with water.
[3]
ii) After the reaction has finished, the teacher adds a few drops of universal indicator to the solution in the trough.
Explain the colour of the universal indicator after it is added to the solution.
[2]
iii) Write a chemical equation for the reaction of lithium with water.
[2]
A student does a flame test to see if a white solid contains sodium ions.
She cleans a platinum wire before using it for the flame test.
Explain why the student needs to clean the platinum wire.
[2]
Which of these is the colour of the flame if the solid contains sodium ions?
green
lilac
red
yellow
Potassium sulfate (K2SO4) is an ionic compound.
i) Give the formula of each ion in potassium sulfate.
[1]
potassium ion ..................
sulfate ion ...............
ii) The melting point of potassium sulfate is 1069 °C.
Explain why potassium sulfate has a high melting point.
Refer to structure and bonding in your answer.
[4]
Was this exam question helpful?
When lithium, a Group 1 metal, reacts with water, two products are formed.
Which is the correct balanced symbol equation, including state symbols, that represents this reaction?
Li (s) + 2H2O (l) → Li(OH)2 (l) + H2 (g)
2Li (s) + 2H2O (l) → 2LiOH (aq) + H2 (g)
2Li (s) + H2O (l) → Li2O (aq) + H2 (g)
2Li (s) + 2H2O (l) → 2LiOH (l) + O2 (g)
Was this exam question helpful?
This question is about some elements in Group 1 of the Periodic Table.
The table gives some statements about the reaction of potassium with water. Place ticks () in three boxes to show which three statements are correct.
Statement | |
potassium reacts more vigorously than sodium when added to water | |
potassium sinks to the bottom of the water | |
bubbles of oxygen gas are produced | |
a lilac flame is seen | |
potassium moves around | |
a solution of potassium oxide is formed |
After the reaction of potassium with water is complete, a few drops of universal indicator are added to the solution formed. The universal indicator turns purple.
i) Suggest a value for the pH of the solution.
[1]
ii) Give the formula of the ion responsible for this pH value.
[1]
Sodium burns in oxygen to produce sodium oxide. Complete the equation for this reaction.
..........Na + ..........O2 → ..........Na2O
Was this exam question helpful?
The position of an element in the Periodic Table can be used to predict its properties.
Which of the following statements could not be predicted using the trends in Group 1?
Rubidium has a lower melting point than lithium
Lithium is softer than potassium
Sodium will tarnish more quickly than lithium
Caesium is more reactive than potassium
Was this exam question helpful?
Lithium, sodium and potassium are the first three elements in Group 1 of the Periodic Table.
Suggest why these three elements are all stored in paraffin oil.
Caesium, Cs, is below potassium in Group 1.
i) Give a similarity and a difference between the reactions of potassium with water and caesium with water.
similarity..........................................................
difference........................................................
[2]
ii) Give the chemical equation for the reaction between caesium and water.
[2]
A student investigates the temperature change in the reaction between dilute acids and solutions of Group 1 hydroxides.
He uses this apparatus.
This is the student’s method:
Measure the temperature of 50 cm3 of hydrochloric acid
Pour the acid into a polystyrene cup
Add 50 cm3 of sodium hydroxide solution to the acid
Measure the maximum temperature of the mixture
i) Suggest what could be added to the apparatus to improve the experiment.
[1]
ii) Explain a change to the method that would improve the accuracy of the experiment.
[2]
These are the student’s results:
Temperature of hydrochloric acid = 19.9 °C
Maximum temperature of mixture = 26.5 °C
i) Calculate the energy change, Q, in joules for this reaction.
[mass of 1.0 cm3 of mixture = 1.0 g]
[for the mixture, c = 4.2 J / g / °C]
Q = .............................................. J
[3]
ii) In the student’s reaction between hydrochloric acid and sodium hydroxide, 0.050 mol of water forms.
Calculate the molar enthalpy change, ∆H, in kJ / mol for this reaction.
∆H = .............................................. kJ / mol
[2]
Was this exam question helpful?
This question is about some Group 1 metal oxides.
When lithium is exposed to oxygen, it is oxidised and traces of lithium peroxides are produced.
i) Explain why the formation of lithium oxide is a redox reaction.
[3]
ii) Lithium oxide and a gas are produced by the thermal decomposition of lithium peroxide, Li2O2.
Write the balanced chemical equation for this reaction. State symbols are not required.
[2]
Lithium oxide can also be produced by heating lithium hydroxide.
2LiOH → Li2O + H2O
State the type of reaction that occurs during this process.
The oxidation of potassium can produce potassium oxide, K2O, and potassium superoxide, KO2.
Compare the oxidation of potassium with the combustion of carbon.
Potassium superoxide is sometimes used as a water dehumidifier, carbon dioxide scrubber and oxygen generator on board space craft and submarines.
As it absorbs and reacts with carbon dioxide, it locks the carbon dioxide up as potassium carbonate and releases oxygen.
i) Write the balanced chemical equation for this chemical reaction. State symbols are not required.
[2]
ii) Determine the number of moles of carbon dioxide absorbed and the number of moles of oxygen released by one mole of potassium superoxide.
[2]
Was this exam question helpful?