Key Calculations quiz Loading... 1. 25 cm³ of sodium chloride solution has a concentration of 0.5 mol/dm³. What amount of sodium chloride does it contain?12.5 mol0.0125 mol1.25 mol0.05 molQuestion 1 of 17 Loading... 2. Use Q=mcΔT and c=4.18J/°C/g. A spatula of sodium fluoride is put into a boiling tube with 25cm³ of water. The temperature drops from 22.0°C to 18.6°C. What is the total heat energy change?1944 J1944 kJ355 kJ/mol355 JQuestion 2 of 17 Loading... 3. A graph shows the solubility of sodium chloride in water at 50°C is 34g/100g. At that temperature, what mass of sodium chloride will dissolve in 200g water?68g0.68g0.34g17gQuestion 3 of 17 Loading... 4. What is meant by the term molecular formula?A chemical formula that shows the simplest ratio of the numbers of atoms in a compoundA chemical formula that shows the actual numbers of the different types of atoms in a moleculeA method of calculating the ratios of masses in an equationA method of calculating the mass needed to make a certain yield in an equationQuestion 4 of 17 Loading... 5. State the units of molar enthalpy change.mol/⁰CkJ/molJ/⁰C/molkJ/⁰CQuestion 5 of 17 Loading... 6. Calculate the relative formula mass(Mr) of ammonium nitrate (NH₄NO₃)66804548Question 6 of 17 Loading... 7. Complete the following expression: amount (in moles) = mass / Mᵣamount (in moles) x MᵣMᵣ / massAᵣ / MᵣQuestion 7 of 17 Loading... 8. A compound that contained 24.24% Carbon. 4.04% Hydrogen and 71.72% Chlorine and has a relative molecular mass of 99. Calculate the empirical formula and the molecular formula.Empirical formula is CH₂Cl. Molecular formula is C₂H₄Cl₂Empirical formula is C₂H₄Cl₂. Molecular formula is C₂H₄Cl₂Empirical formula is C₂H₄Cl₂. Molecular formula is CH₂ClEmpirical formula is CH₂Cl. Molecular formula is CH₂ClQuestion 8 of 17 Loading... 9. State the expression for calculating molar volume of a gas.Molar volume = amount (in grams) / 24 dm³ (or 24,000 cm³)Molar volume = amount (in moles) / 24 dm³ (or 24,000 cm³)Molar volume = amount (in grams) x 24 dm³ (or 24,000 cm³)Molar volume = amount (in moles) x 24 dm³ (or 24,000 cm³)Question 9 of 17 Loading... 10. What are the units for amount in Chemistry?Molesg per 100g of solventmol/dm³GramsQuestion 10 of 17 Loading... 11. What mass of calcium bromide will fully react with 71g of chlorine?200g240 g480 g120 gQuestion 11 of 17 Loading... 12. A sample of bromine contained the two isotopes in the following proportions: bromine-79 = 50.7% and bromine-81 = 49.3%. Calculate the relative atomic mass of bromine((79x50.7)+(81x49.3))/100 = 79.99(81x79)/100 = 63.99(81 + 79)/2 = 80((81x50.7)+(79x49.3))/100 = 80.01Question 12 of 17 Loading... 13. State the steps for calculating empirical formula1) Aᵣ/mass. 2) divide by the largest. 3) Give the ratio has a whole number. 4) State final empirial formula1) Aᵣ/mass. 2) divide by the smallest. 3) Give the ratio has a whole number. 4) State final empirial formula1) mass/Aᵣ. 2) divide by the largest. 3) Give the ratio has a whole number. 4) State final empirial formula1) mass/Aᵣ. 2) divide by the smallest. 3) Give the ratio has a whole number. 4) State final empirial formulaQuestion 13 of 17 Loading... 14. In a chemical reaction, the overall molar enthalpy is -87 kJ/mol. Is this reaction exothermic or endothermic?Depends on the temperature of the surroundingsDepends on the reagentsExothermicEndothermicQuestion 14 of 17 Loading... 15. To determine the formula of a metal oxide by combustion, magnesium is heated in a crucible. Why is a lid lifted from time to time?To allow carbon dioxide to escapeTo stop the crucible heating up too muchTo allow oxygen in so the magnesium fully reactsTo allow some magnesium oxide smoke to escapeQuestion 15 of 17 Loading... 16. In the thermal decomposition of calcium carbonate, we might expect 50g of calcium carbonate to produce 28g of calcium oxide. If instead only 24g of calcium oxide is produced, what is the percentage yield?56 %0.56 %0.857 % 85.7 %Question 16 of 17 Loading... 17. Name this piece of lab equipmentburettemeasuring cylinderpipettegas syringeQuestion 17 of 17 Loading... Related Posts:The entire quiz question bank!The entire quiz question bank (Double only)!Equilibria (triple) quizCondensation Polymers quizElectrolysis quizAlcohols & Carboxylic Acids quiz Hydr0Gen2020-02-16T17:35:16+00:00Categories: Uncategorized|Tags: Quiz, Topic: Key Calculations| Share This Story, Choose Your Platform! FacebookXRedditLinkedInTumblrPinterestVkEmail