Edexcel GCSE Combined Science Paper 3: Chemistry 1 Higher June 2019 question paper 1SC0/1CH

In Figure 1, the letters A, E, G, J, X and Z show the positions of six elements in the periodic table.

These letters are not the symbols of the atoms of these elements.

Using the letters A, E, G, J, X and Z

give the letters of the two elements that are non-metals

give the letters of two elements in period 2

give the letter of an element that normally forms an ion with a charge of +1.

Element E has an atomic number of 5. In a sample of E there are two isotopes. One isotope has a mass number of 10 and the other isotope has a mass number of 11.

Explain, in terms of subatomic particles, what is meant by the term isotopes.

All atoms of element E in this sample contain

Element X has an atomic number of 18.

State the electronic configuration of an atom of element X.

In an experiment, 3.5 g of element A reacted with 4.0 g of element G to form a compound.

Calculate the empirical formula of this compound. (relative atomic masses: A = 7, G = 16)

You must show your working.

empirical formula of this compound =_........

(a) Water, acidified with sulfuric acid, is decomposed by electrolysis. The water is decomposed to produce hydrogen and oxygen.

A sample of hydrogen is mixed with air and ignited.

State what would happen.

Throughout the experiment the volume of hydrogen and the volume of oxygen are measured at two-minute intervals.

The results are shown in Figure 2.

Describe, using the data in Figure 2, what the results show about the volumes of hydrogen and of oxygen produced in this experiment.

Molten lead bromide is electrolysed.

The products of this electrolysis are

Calcium nitrate and calcium carbonate are both ionic compounds.

Calcium nitrate mixed with water behaves as an electrolyte. Calcium carbonate mixed with water does not behave as an electrolyte.

Explain, in terms of solubility and movement of ions, this difference in behaviour.

When molten zinc chloride is electrolysed, zinc ions, Zn²⁺, form zinc atoms.

Write the half equation for this reaction.

(a) One way to extract metals from land contaminated with metal compounds is phytoextraction. When plants grow they absorb metal ions through their roots. The plants are harvested, dried and burned forming an ash. The ash contains metal compounds.

Plants were grown in a piece of ground contaminated with nickel compounds.

1 kg of the ash from these plants contained 142.0 g of nickel compounds.

Calculate the percentage by mass of nickel compounds in the ash.

percentage by mass =_........

Nickel is extracted from nickel compounds.

State an advantage of extracting nickel by phytoextraction rather than from its ore.

Some nickel ores contain nickel sulfide.

In the first stage of extracting nickel from nickel sulfide, the nickel sulfide, NiS, is heated in air to form nickel oxide, NiO, and sulfur dioxide.

Write the balanced equation for this reaction.

In the final stage of the extraction process, a nickel compound is electrolysed to produce pure nickel.

An advantage of producing a metal by electrolysis is that

In a different method of obtaining nickel, the process produces a mixture of the liquids nickel tetracarbonyl and iron pentacarbonyl.

The boiling point of nickel tetracarbonyl is 43 °C. The boiling point of iron pentacarbonyl is 103 °C. These two liquids mix together completely.

Describe the process used to separate these two liquids.

Hydrated copper sulfate, CuSO₄.5H₂O, is a blue solid. Anhydrous copper sulfate, CuSO₄, is a white solid.

Heat energy is needed to convert hydrated copper sulfate to anhydrous copper sulfate. This is a reversible reaction.

Devise an experiment to show that this is a reversible reaction.

Hydrogen reacts with iodine to form hydrogen iodide. Iodine gas is purple and hydrogen iodide gas is colourless.

Hydrogen and iodine are placed in a sealed container. The container is left until equilibrium is reached.

The conditions are changed favouring the forward reaction.

Explain what you would see.

Calculate the number of atoms combined in one mole of copper iodide, CuI₂. (Avogadro constant = 6.02 × 10²³)

number of atoms =_........

Pieces of zinc react with copper sulfate solution. Zinc sulfate solution is colourless.

Describe what you would see when an excess of zinc is added to copper sulfate solution and the mixture left until the reaction is complete.

This reaction is described as a redox reaction.

Explain, in terms of electrons, which particles have been oxidised and which particles have been reduced in this reaction.

The copper sulfate solution used has a concentration of 15.95 g dm⁻³.

Calculate the number of moles of copper sulfate, CuSO₄, in 50.00 cm³ of this solution. (relative atomic masses: O = 16, S = 32, Cu = 63.5)

number of moles of copper sulfate =_........ mol

In another experiment, 0.043 mol of copper sulfate, CuSO₄, is used.

Calculate, to one decimal place, the minimum mass of zinc that must be added to react with all the copper sulfate. (relative atomic mass: Zn = 65)

mass =_........ g

(a) X and Y are solutions of two different acids. The concentration of acid in each solution, in mol dm⁻³, is the same. Solution X has a pH of 3.40 and solution Y has a pH of 4.40.

State what could be used to measure these pH values of 3.40 and 4.40.

What is the concentration of hydrogen ions in solution X compared with that in solution Y ?

An experiment is planned to record the change in pH as a powdered base is added to 50 cm³ dilute hydrochloric acid.

The method suggested is

step 1 add dilute hydrochloric acid up to the 50 cm³ mark on a beaker

step 2 add one spatula of the base and stir

step 3 measure the pH of the mixture

step 4 repeat steps 2 and 3 until the pH stops changing.

State how you could change the method so that the amounts of dilute hydrochloric acid and of the base can be measured more accurately.

dilute hydrochloric acid_........

base_........

During the experiment the pH changes from 2 to 10. If phenolphthalein indicator is added at the beginning of the experiment, a colour change occurs as the base is added.

State the colour change that occurs.

colour at start_........

colour at end_........

Explain, in terms of the particles present, why the pH increases during the experiment.

*(c) Some properties of four solids, A, B, C and D, are shown in Figure 3.

The solids, in no particular order, are copper carbonate, copper oxide, magnesium metal and sodium hydroxide.

Identify the solids A, B, C and D, explaining how the information in Figure 3 supports the identification of each solid.