Chemistry Paper 1 | AQA GCSE | Brian Peter | 2025 | Detailed Exam Questions with Model Ans, Exams of Chemistry

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CHEMISTRY

PAPER 1 AQA

GCSE.

BRIAN PETERI

mol = .... x ..... vol = ..../.... ...... / ..... = ..... dm .... × ...... = .... cm - CORRECT ANSWER 0.0045 / 0.15 = 0.03 dm 0.03 × 1000 = 30 cm mol = conc x vol Volume of acid = 30 vol = mol/conc" "Explain why calcium reacts more vigorously than magnesium with hydrochloric acid of the same concentration. A calcium atom is larger than a magnesium atom a calcium atom is .... than a magnesium atom meaning it has .... shells this means that the outer shell of calcium is less ....... attracted to the nucleus then magnesium meaning it is easier to .... an electron for calcium - CORRECT ANSWER a calcium atom is larger than a magnesium atom meaning it has more shells this means that the outer shell of calcium is less electrostatically attracted to the nucleus then magnesium meaning it is easier to lose an electron for calcium" Give two observations made when potassium reacts with water. - CORRECT ANSWER

1. lilac flame
2. potassium starts to float in water" "Potassium hydroxide solution is produced when potassium reacts with water. What is the colour of universal indicator when added to potassium hydroxide solution Colour of universal indicator ....../....... Reason ...... ...... has ...... (......) so it is ...... - CORRECT ANSWER colour - blue/purple Reason - potassium hydroxide has hydroxide (OH-) so it is alkali" "The elements in Group 7 are called the halogens.

A more reactive halogen can displace a less reactive halogen from a solution of its salt. Which combination of solutions will produce a reaction when mixed? Tick (v) one box. [1 mark Chlorine and potassium fluoride Chlorine and potassium bromide Bromine and potassium fluoride Bromine and potassium chloride - CORRECT ANSWER chlorine and potassium bromide" "7] Which of the following describes the trends going down Group 7? Tick (v) one box. Relative atomic mass decreased and boiling point decreases Relative molecular mass decreases and boiling point increases. Relative molecular mass increases and boiling point decreases Relative molecular mass increases and boiling point increases - CORRECT ANSWER Relative molecular mass increases and boiling point increases" "Model a is a ball to positive charge Model B is a proton in the middle with electrons around it What is model A and B? - CORRECT ANSWER Model A - Plum pudding model Model B - Nuclear model" "Compare Plum pudding with the model of the atom used today plum pudding has a ball of ...... charge with embedded ..... whereas today the nucleus contains the ...... charge at the centre of an atom today the model of the atom has ..... in shells that surround the ..... model used today also has ..... in the nucleus whereas ...... weren't discovered when the plum pudding model was published - CORRECT ANSWER plum pudding has a ball of

"Calculate the mean highest temperature reached add them up and divide by 4 range is 0.6 so + or - 3 Mean highest temperature reached = 37.5 +- 3 - CORRECT ANSWER add them up and divide by 4 range is 0.6 so + or - 3 Mean highest temperature reached = 37.5 +- 3" "The results show random errors. The student did not make any measuring errors. Suggest one reason for the random errors in this experiment. - CORRECT ANSWER copper sulfate initial temp may have been different" "This question is about ionic compounds and electrolysis Calcium chloride is an ionic compound. Calcium and chlorine react to produce calcium chloride. Describe what happens to calcium atoms and chlorine atoms when the ionic compound calcium chloride is formed. calcium ..... .. electrons and give .. to each chlorine atom so they can all gain a ..... outer shell this results in Ca..+ and ..CI- these ............... attract to form calcium chloride (CaCI2) - CORRECT ANSWER calcium loses 2 electrons and give 1 to each chlorine atom so they can all gain a full outer shell this results in Ca2+ and 2CI- these electrostatically attract to form calcium chloride (CaCI2)" "Solid calcium chloride cannot be electrolysed.

Give one reason why. ions aren't able to .... and .... ..... in a solid - CORRECT ANSWER ions aren't able to flow and carry charge in a solid" "Describe how a hydrogen fuel cel produces a potential difference. hydrogen .... electrons and these are ..... back when hydrogen reacts with oxygen to form water and these electrons carry charge which causes a ...... ....... - CORRECT ANSWER hydrogen lose electrons and these are gained back when hydrogen reacts with oxygen to form water and these electrons carry charge which causes a potential difference" "Iron is a metal. Describe how iron conducts thermal energy. Iron is a ..... metal which means it's ...... electrons are able to carry .... energy through the metal - CORRECT ANSWER Iron is a transition metal which means it's delocalised electrons are able to carry thermal energy through the metal" "Pure iron is too soft for many uses. Explain why mixing iron with other metals makes alloys which are harder than pure iron. iron and other metals have different .... atoms which means that the other metal will .... irons layers which makes it harder for the ...... to slide over each other - CORRECT ANSWER iron and other metals have different sized atoms which means that the other metal will distort irons layers which makes it harder for the lavers to slide over each other" "when iron reacts wth chorine, O.12 mol of iron reacts with 0.18 mol of chorine (Cl2) Which is the correct equation for the reaction? Tick (v) one box. (1 mark] Fe + Cla -> FeCl Fe + 3Cl -› FeCl 2Fe + Ch -* 2 FeCl 2Fe + 3Cl -› 2FeCl3 - CORRECT ANSWER 2Fe + 3Cl -› 2FeCl3" "The most common oxides of iron are Fe2O3 and Fe3O o 7. 4 What is the ratio of the numbers of ions in Fe304? Tick (V) one box. 2 Fe2+ : 1 Fe3t: 4 02- 1 Fe 2+ : 2 Fe3+ : 4 O2-

Copper carbonate + sulfuric acid ——> ..... ..... + ..... - CORRECT ANSWER Copper carbonate + sulfuric acid ——> Copper sulfate + water" "One observation which shows that the copper carbonate is in excess? - CORRECT ANSWER Residue of copper carbonate at the bottom of the beaker" "One reason for filtering the previous mixture? - CORRECT ANSWER To remove excess copper" "What equipment piece is used to warm the filtrate gently? - CORRECT ANSWER water bath" "The maximum theoretical mass of the salt that could be produced using 50 cm^3 of the sulfuric acid is 12.5 g. The percentage yield of the salt is 92.8%. Calculate the mass of salt actually produced. Use the equation: mass of salt actually produced % yield = maximum theoretical mass of salt that could be produced × [3 marks] - CORRECT ANSWER 92.8 = (mass / 12.5)× 100 0.928 x 12.5 = mass =11.6" "Some salts can be produced by reacting sulfuric acid with a metal, Neither copper nor sodium is used to produce a salt with sulfuric acid. Give one reason why each metal is not used. copper has a .... ....... so it will take a ....... time to react sodium has a ..... ....... so it will react ........ with sulfuric acid which is a ...... - CORRECT ANSWER copper has a low reactivity so it will take a long time to react sodium has a high reactivity so it will react aggressively with sulfuric acid which is a hazard" "This question is about the periodic table. Sodium and potassium are in Group 1 of the periodic table. Give one similarity and one difference between the electronic structures of sodium and potassium.

Similarity - Both have .. ....... in their outer shell difference - sodium has .... .... shells but potassium has ... .... shells - CORRECT ANSWER Similarity - Both have 1 electron in their outer shell difference - sodium has 2 full shells but potassium has 3 full shells" "Group 1 elements react with water. ""Name the product formed at the negative electrode when aqueous calcium chloride solution is electrolysed - CORRECT ANSWER hydrogen (less reactive than calcium)" "What is the half equation for the reaction at the positive electrode when aqueous calcium chloride solution is electrolysed? Tick (v) one box. 2Cl- -> Cl2 + 2e- Cl2 + 2e- -> 2Cl 4OH^-> 02 + 2H20 + 4e- 02 + 2H20 + 4é- -> 40H - CORRECT ANSWER 2Cl- -> Cl2 + 2e-" "Copper chromate solution contains the ions Cu2+ and CrO4 ^2-. Explain the results shown in Figure 5 copper is .... and chromate is ..... copper is a .... ion so it will be attracted to the negative electrode chromate is a ...... ion and will be attracted to the positive ion - CORRECT ANSWER copper is blue and chromate is yellow copper is a positive ion so it will be attracted to the negative electrode chromate is a negative ion and will be attracted to the positive ion" "Write the symbols of the 5 metals in order of reactivity Justify your answer. Most reactive - Mg Zn Ni Cu Ag