1. 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?

Question 1 of 17

2. Use Q=mcΔT and c=4.18J/°C/g. A strip of magnesium is added to a beaker with 200cm³ of copper (II) sulfate. The temperature starts at 21.7°C and rises to a maximum of 23.1°C. What is the total heat energy change?

Question 2 of 17

3. 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.

Question 3 of 17

4. In a chemical reaction, the overall molar enthalpy is -87 kJ/mol. Is this reaction exothermic or endothermic?

Question 4 of 17

5. 25 cm³ of sodium chloride solution has a concentration of 0.5 mol/dm³. What amount of sodium chloride does it contain?

Question 5 of 17

6. 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

Question 6 of 17

7. What volume does 0.5 moles of ethene gas occupy (at rtp)

Question 7 of 17

8. What mass of calcium bromide will fully react with 71g of chlorine?

Question 8 of 17

9. 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?

Question 9 of 17

10. 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?

Question 10 of 17

11. What are the units for amount in Chemistry?

Question 11 of 17

12. Complete the following expression: amount (in moles) =

Question 12 of 17

13. Calculate the relative formula mass(Mr) of ammonium nitrate (NH₄NO₃)

Question 13 of 17

14. To determine the formula of a metal oxide by combustion, magnesium is heated in a crucible. Why is the crucible is cooled, weighed, reheated, cooled, re-weighed, and so on?

Question 14 of 17

15. State the units of molar enthalpy change.

Question 15 of 17

16. Name this piece of lab equipment

Question 16 of 17

17. What is meant by the term molecular formula?

Question 17 of 17


 

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