Grade 10 Stoichiometry Questions And Answers

Grade 10 Stoichiometry Questions and Answers: Tips and Tricks Stoichiometry is a branch of chemistry that deals with the quantitative relationship between reactants and products in chemical reactions. It is a fundamental concept in chemistry, and it is essential to understand it to excel in the subject. In this article, we will discuss some grade 10 stoichiometry questions and answers, along with some tips and tricks to solve them. Before we dive into the questions, let’s understand some basic concepts of stoichiometry. The first thing you need to know is the mole concept. A mole is a unit of measurement that is used to measure the amount of a substance. One mole of any substance contains 6.022 x 10^23 particles. The second thing you need to know is the balanced chemical equation. A balanced equation shows the number of reactants and products in a chemical reaction. Now let’s move on to some grade 10 stoichiometry questions and answers. Question 1: How many moles of water are produced when 2 moles of hydrogen gas react with 1 mole of oxygen gas? Answer: The balanced chemical equation for the reaction is: 2H₂ + O₂ → 2H₂O According to the equation, 2 moles of hydrogen gas react with 1 mole of oxygen gas to produce 2 moles of water. Therefore, when 2 moles of hydrogen gas react with 1 mole of oxygen gas, 2 moles of water are produced. Question 2: What is the mass of sodium chloride (NaCl) produced when 5 g of sodium (Na) reacts with excess chlorine (Cl₂)? Answer: The balanced chemical equation for the reaction is: 2Na + Cl₂ → 2NaCl According to the equation, 2 moles of sodium react with 1 mole of chlorine to produce 2 moles of sodium chloride. To find the mass of sodium chloride produced, we need to first calculate the number of moles of sodium used. The molar mass of sodium is 23 g/mol. Therefore, 5 g of sodium is equal to 5/23 moles of sodium. Now, according to the balanced equation, 2 moles of sodium react with 1 mole of chlorine to produce 2 moles of sodium chloride. Therefore, 5/23 moles of sodium will react with (5/23)/2 moles of chlorine to produce (5/23) moles of sodium chloride. The molar mass of sodium chloride is 58.5 g/mol. Therefore, (5/23) moles of sodium chloride is equal to (5/23) x 58.5 = 12.7 g of sodium chloride. Question 3: What is the percentage yield of a reaction if the theoretical yield is 25 g and the actual yield is 20 g? Answer: The percentage yield is calculated using the following formula: Percentage yield = (actual yield / theoretical yield) x 100% In this case, the actual yield is 20 g, and the theoretical yield is 25 g. Therefore, the percentage yield = (20 / 25) x 100% = 80%. Now that we have seen some examples of grade 10 stoichiometry questions and answers, let’s discuss some tips and tricks to solve them. Tip 1: Always start with a balanced chemical equation. A balanced equation is essential to calculate the number of moles of reactants and products involved in the reaction. Tip 2: Always convert the given quantities into moles. Stoichiometry calculations are always done in moles, so it is essential to convert the given quantities into moles before solving the problem. Tip 3: Use the mole ratio from the balanced equation to calculate the number of moles of the required substance. The mole ratio helps to calculate the number of moles of the required substance based on the number of moles of the reactants involved in the reaction. In conclusion, stoichiometry is an important concept in chemistry and requires a good understanding of basic concepts and formulas. By following the tips and tricks mentioned above, you can easily solve grade 10 stoichiometry questions and answers.