StoichiometrySE_Key hemistry questions with answers 2022

A 250 mL glass of orange juice contains 22 grams of sugar. How much sugar is in a two-liter (2,000 mL) bottle of orange juice? 176 grams of sugar 2. It requires two sticks of butter to make a batch of 20 cookies. How much butter will it take to make 150 cookies? 15 sticks of butter Gizmo Warm-up Just as a cook follows a recipe to decide how much of each ingredient to add, a chemist uses stoichiometry to determine the amounts of substances involved in chemical reactions. The Stoichiometry Gizmo™ allows you to try your hand at figuring out the amounts of reactants and products that take part in a chemical reaction. To begin, check that this equation is shown: Fe2O3 + 3CO  2Fe + 3CO2 1. Look at the coefficients (such as the “3” in 3CO) in front of each substance in the equation. The coefficients tell you how many molecules or atoms take part in a chemical reaction. In the spaces below, list the number of each molecule or atom in the equation: Fe2O3 1 CO 3 Fe 2 CO2 3 2. In a balanced equation, the same number of each kind of atom is shown on each side of the equation. Calculate the number of iron (Fe), oxygen (O), and carbon atoms (C). Reactants Iron: 2 Oxygen: 6 Carbon: 3 Products Iron: 2 Oxygen: 6 Carbon: 3 This study source was downloaded by from CourseH on :33:33 GMT -06:00 Based on these values, is the equation balanced? Yes This study source was downloaded by from CourseH on :33:33 GMT -06:00 Activity A: Moles Get the Gizmo ready:  Check that the equation is still: Fe2O3 + 3CO  2Fe + 3CO2  If not, click New equation until it reappears. Introduction: A mole is: A) A mammal known for digging up gardens. B) A small, dark spot on the skin. C) A spy embedded within an enemy government. D) 6.02 × 1023 particles of a substance. E) All of the above. The correct answer, of course, is E. In chemistry, the mole (mol) is defined as an amount of a substance that contains 6.02 × 1023 particles of that substance. This number, called Avogadro’s number, is special because this number of particles has a mass in grams that is equal to the mass in universal mass units of a single particle of the substance. Question: How do scientists find the molecular mass and molar mass of a substance? 1. Calculate: The molecular mass of a molecule is the sum of the masses of each atom in the molecule. The unit of molecular mass is the universal mass unit (u). Iron’s atomic mass is 55.85 u, carbon’s mass is 12.01 u, and oxygen’s mass is 16.00 u. A. Calculate the molecular mass of carbon monoxide (CO) by adding the atomic mass of carbon and the atomic mass of oxygen: 28.01 u B. Calculate the molecular mass of carbon dioxide (CO2): 44.01 u C. Calculate the molecular mass of iron (III) oxide (Fe2O3): 159.70 u 2. Infer: A mole of a substance has a mass in grams that is equal to the molecular mass. For example, a carbon atom has a mass of 12.01 u. A mole of carbon has a mass of 12.01 g. Based on their molecular masses, list the molar mass of each substance: Fe2O3 159.70 g CO 28.01 g Fe 55.85 g CO2 44.01 g Check your answers on the Gizmo by inspecting the middle row of tiles on the right side of the Gizmo. These tiles show the units “1 mol” on top and “g” below. 3. Practice: Hydrogen has an atomic mass of 1.01 u. What is the molar mass of these substances? H2O 18.02 g CH4 16.05 g H2CO3 62.03 g C6H12O6 180.18 g