Key Calculations quiz Loading... 1. 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 stop the crucible heating up too muchTo allow oxygen in so the magnesium fully reactsTo allow carbon dioxide to escapeTo allow some magnesium oxide smoke to escapeQuestion 1 of 17 Loading... 2. State the expression for calculating molar concentrationMolar concentration = Amount (in moles)/volume (in dm³)Molar concentration = Amount (in moles)/volume (in cm³)Molar concentration = volume (in dm³) / Amount (in moles)Molar concentration = Amount (in moles) x volume (in cm³)Question 2 of 17 Loading... 3. Name this piece of lab equipmentgas syringemeasuring cylinderburettepipetteQuestion 3 of 17 Loading... 4. 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 CH₂ClEmpirical formula is C₂H₄Cl₂. Molecular formula is CH₂ClEmpirical formula is CH₂Cl. Molecular formula is C₂H₄Cl₂Empirical formula is C₂H₄Cl₂. Molecular formula is C₂H₄Cl₂Question 4 of 17 Loading... 5. 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?0.34g0.68g68g17gQuestion 5 of 17 Loading... 6. Calculate the relative formula mass(Mr) of calcium carbonate (CaCO₃)1001205068Question 6 of 17 Loading... 7. A sample of hydrogen chloride gas has a volume of 48 dm³. What amount of hydrogen chloride is this?48 moles2 moles1 mole24 molesQuestion 7 of 17 Loading... 8. Complete the following expression: mass = Mᵣ / amount (in moles)amount (in moles) / Mᵣamount (in moles) x MᵣAᵣ / MᵣQuestion 8 of 17 Loading... 9. 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?0.857 % 56 %85.7 %0.56 %Question 9 of 17 Loading... 10. Use Q=mcΔT and c=4.18J/°C/g. 25cm³ of sulfuric acid is put into a boiling tube. The starting temperature is 21°C. A spatula of iron filings is added. After a while the temperature reaches 33°C. What is the total heat energy change?3383 J1254 J2.153 kJ2153 JQuestion 10 of 17 Loading... 11. What is the meaning of the word mole in Chemistry?A mole is a small burrowing mammalMoles are the units for amount of substance. 1 mole of an element is its atomic number in grams (e.g. 1 mole of magnesium is 12 g)Moles are the units for amount of substance. (1 mole is 10 g of a substance)Moles are the units for amount of substance. 1 mole of a substance is its relative formula mass in grams (e.g. 1 mole of magnesium is 24 g)Question 11 of 17 Loading... 12. What mass of carbon dioxide is produced when 24g of carbon undergoes completely combustion?88g24 g44 g176 gQuestion 12 of 17 Loading... 13. What is meant by the term molecular formula?A chemical formula that shows the actual numbers of the different types of atoms in a moleculeA chemical formula that shows the simplest ratio of the numbers of atoms in a compoundA method of calculating the ratios of masses in an equationA method of calculating the mass needed to make a certain yield in an equationQuestion 13 of 17 Loading... 14. State the units of molar enthalpy change.mol/⁰CkJ/⁰CJ/⁰C/molkJ/molQuestion 14 of 17 Loading... 15. In a chemical reaction, 250 kJ/mol is taken to break all the bonds and 280 kJ/mol is released when new bonds are formed. What is the overall molar enthalpy of the reaction?-30 kJ/mol+530 kJ/mol-530 kJ/mol+30 kJ/molQuestion 15 of 17 Loading... 16. What is the empirical formula of a compound in which 0.48 g of carbon combines with 0.08 g of hydrogen and 0.64 g of oxygen?C₂H₄O₂CH₄OCH₂OC₄H₂OQuestion 16 of 17 Loading... 17. 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((81x50.7)+(79x49.3))/100 = 80.01(81x79)/100 = 63.99(81 + 79)/2 = 80Question 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