Introduction
GRADE 11
STOICHIOMETRY
12 SEPTEMBER 2022
GOOD DAY STUDENTS
Look the introduction of the lesson in the link below.
https://drive.google.com/file/d/1_5DXCKtmYSA8qe4bHeswFNIMR5b7oVk_/view?usp=sharing
Task
STOICHIOMETRIC CALCULATIONS AND VOLUME IN GASES
QUESTION 1
1. A 3,7 g sample of an antacid (which contains mostly calcium carbonate) is dissolved in water. the final solution has a volume of 500 ml. 25 ml of this solution then pipetted into a conical flask and titrated with hydrochloric acid. It is found that 20 ml of the hydrochloric acid completely neutralises the antacid solution.
(a) Define the word concentration.
(b) Write the above word equation in chemical formula equation. (2)
(b) What is the concentration of the hydrochloric acid? (6)
Question 2
2. 130 g of magnesium chloride( MgCl2) is dissolved in 300 ml of water.
(a) calculate the concentration of the solution. (4)
(b) What mass of magnesium chloride would need to be added for the concentration to become 6,7 mol-dm-3 (5)
Question 3
3.
(a) Define the term volume. (2)
(b)What volume of oxygen is needed for the complete combustion of 5 of magnesium to form magnesium oxide? (5)
Process
INSTRUCTIONS OF THE TASK
- Write everything that is on the task
- Round-off ONLY the finally answer
- Round-off the final answer into 2 decimals
- Show all step when calculating each problem
- Use scientific calculator for precise answer
- Use the periodic table when writing the chemical equations
- Use correct conversion
- Write the isUnits in final answer
Evaluation
THE MARKS WILL BE ALLOCATED ACCORDING TO THE FOLLOWING RUBIC.
NB: CONSULT THE RUBRIC WHEN WRITING THE TASK
| Criteria rating | Poor | Good | Better | Excellent |
| Conversion | No conversion | Conversion with minor errors | Conversion with little understanding | Accurate conversion |
| IsUnits | No IsUnits | - | - | Precise IsUnit |
| Calculation steps | No steps | Few steps | Step with minor problem | All steps presented |
Conclusion
Stoichiometric calculations
Stoichiometry is the calculation of the quantities of reactants and products in chemical reactions. It is important to know how much product will be formed in a chemical reaction, or how much of a reactant is needed to make a specific product.
The following diagram shows how the concepts that we have learnt in this chapter relate to each other and to the balanced chemical equation:
The purpose of stoichiometry is to tells us what what quantity of each reactant we need in order to get enough of our desired products.
After attempting the activity please reflect on how was it and what were your difficulties using this platform, so that I can know where you guys are lacking.
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