W1 Example 4 Answers
- 1. 4a 1ml of water occupies a volume of 1cm3. How many litres will 5cm3 of water occupy?
- 2. 4a • Convert 1ml into litres:
- 3. 4a • Convert 1ml into litres: 1ml = 0.001L
- 4. 4a • Convert 1ml into litres: 1ml = 0.001L • Multiply this by the size of the sample:
- 5. 4a • Convert 1ml into litres: 1ml = 0.001L • Multiply this by the size of the sample: 5cm3 = 5ml = 0.001L x 5 = ퟓ 퐱 ퟏퟎ−ퟑ퐋
- 6. 4b There are 1.4 x 1021L of water in the ocean. What is this in cubic metres?
- 7. 4b • Work out the conversion between cm3 and m3:
- 8. 4b • Work out the conversion between cm3 and m3: 1cm = 0.01m
- 9. 4b • Work out the conversion between cm3 and m3: 1cm = 0.01m 1cm3 = cm x cm x cm = 0.01 x 0.01 x 0.01 m3 = 1 x 10−6m3
- 10. 4b • Work out the conversion between cm3 and m3: 1cm = 0.01m 1cm3 = cm x cm x cm = 0.01 x 0.01 x 0.01 m3 = 1 x 10−6m3 • Work out the conversion between 1L and 1m3:
- 11. 4b • Work out the conversion between cm3 and m3: 1cm = 0.01m 1cm3 = cm x cm x cm = 0.01 x 0.01 x 0.01 m3 = 1 x 10−6m3 • Work out the conversion between 1L and 1m3: 1ml = 1cm3
- 12. 4b • Work out the conversion between cm3 and m3: 1cm = 0.01m 1cm3 = cm x cm x cm = 0.01 x 0.01 x 0.01 m3 = 1 x 10−6m3 • Work out the conversion between 1L and 1m3: 1ml = 1cm3 1 x 10−3L = 1 x 10−6m3
- 13. 4b • Work out the conversion between cm3 and m3: 1cm = 0.01m 1cm3 = cm x cm x cm = 0.01 x 0.01 x 0.01 m3 = 1 x 10−6m3 • Work out the conversion between 1L and 1m3: 1ml = 1cm3 1 x 10−3L = 1 x 10−6m3 1L = 1 x 10−3m3
- 14. 4b • Work out the conversion between cm3 and m3: 1cm = 0.01m 1cm3 = cm x cm x cm = 0.01 x 0.01 x 0.01 m3 = 1 x 10−6m3 • Work out the conversion between 1L and 1m3: 1ml = 1cm3 1 x 10−3L = 1 x 10−6m3 1L = 1 x 10−3m3 • Multiply by the volume of the ocean:
- 15. 4b • Work out the conversion between cm3 and m3: 1cm = 0.01m 1cm3 = cm x cm x cm = 0.01 x 0.01 x 0.01 m3 = 1 x 10−6m3 • Work out the conversion between 1L and 1m3: 1ml = 1cm3 1 x 10−3L = 1 x 10−6m3 1L = 1 x 10−3m3 • Multiply by the volume of the ocean: 1.4 x 1021L = 1.4 x 1021 x 10−3 m3 = ퟏ. ퟒ 퐱 ퟏퟎퟏퟖ퐦ퟑ
- 16. 4c Seawater contains about 142mgL-1of bicarbonate. How many grams of bicarbonate will there be in a 2m3 sample of seawater?
- 17. 4c • Convert 142 mgL-1 into 142 mgm-3:
- 18. 4c • Convert 142 mgL-1 into 142 mgm-3: 1퐿 = 1 푥 10−3푚3
- 19. 4c • Convert 142 mgL-1 into 142 mgm-3: 1퐿 = 1 푥 10−3푚3 1 1 퐿−1 = 1 10−3 푚−3
- 20. 4c • Convert 142 mgL-1 into 142 mgm-3: 1퐿 = 1 푥 10−3푚3 1 1 퐿−1 = 1 10−3 푚−3 1퐿−1 = 103푚−3
- 21. 4c • Convert 142 mgL-1 into 142 mgm-3: 1퐿 = 1 푥 10−3푚3 1 1 퐿−1 = 1 10−3 푚−3 1퐿−1 = 103푚−3 142푚푔퐿−1 = 142 푥 103푚푔푚−3 = 1.42 푥 105푚푔푚−3
- 22. 4c • Convert 142 mgL-1 into 142 mgm-3: 1퐿 = 1 푥 10−3푚3 1 1 퐿−1 = 1 10−3 푚−3 1퐿−1 = 103푚−3 142푚푔퐿−1 = 142 푥 103푚푔푚−3 = 1.42 푥 105푚푔푚−3 • Multiply by the sample size and convert mg to g:
- 23. 4c • Convert 142 mgL-1 into 142 mgm-3: 1퐿 = 1 푥 10−3푚3 1 1 퐿−1 = 1 10−3 푚−3 1퐿−1 = 103푚−3 142푚푔퐿−1 = 142 푥 103푚푔푚−3 = 1.42 푥 105푚푔푚−3 • Multiply by the sample size and convert mg to g: 1.42 푥 105푚푔푚−3 푥 2푚3 = 2.84 푥 105푚푔
- 24. 4c • Convert 142 mgL-1 into 142 mgm-3: 1퐿 = 1 푥 10−3푚3 1 1 퐿−1 = 1 10−3 푚−3 1퐿−1 = 103푚−3 142푚푔퐿−1 = 142 푥 103푚푔푚−3 = 1.42 푥 105푚푔푚−3 • Multiply by the sample size and convert mg to g: 1.42 푥 105푚푔푚−3 푥 2푚3 = 2.84 푥 105푚푔 2.84 푥 105 푥 10−3 = ퟐퟖퟒ품
- 25. 4d There is approximately 1.81 x 1021g of magnesium in the entire ocean. For any sample of seawater, calculate the magnesium content in molL-1.
- 26. 4d • Calculate the number of moles of Mg in the ocean:
- 27. 4d • Calculate the number of moles of Mg in the ocean: 1 mole Mg = 24.305g
- 28. 4d • Calculate the number of moles of Mg in the ocean: 1 mole Mg = 24.305g 1.81 x 1021 24.305 = 7.45 x 1019mol Mg
- 29. 4d • Calculate the number of moles of Mg in the ocean: 1 mole Mg = 24.305g 1.81 x 1021 24.305 = 7.45 x 1019mol Mg • Use the volume of the ocean to work out the overall concentration of Mg in seawater:
- 30. 4d • Calculate the number of moles of Mg in the ocean: 1 mole Mg = 24.305g 1.81 x 1021 24.305 = 7.45 x 1019mol Mg • Use the volume of the ocean to work out the overall concentration of Mg in seawater: 7.45 x 1019mol Mg 1.4 x 1021L = ퟎ. ퟎퟓퟑ퐦퐨퐥퐋−ퟏ