Under certain conditions, water can be separated into oxygen and hydrogen gases according to the equation 2H2O → 2H2 + O2. In a lab, 112g of hydrogen gas and 888g of oxygen gas were collected. Student A says that the amount of water to start cannot be determined, but Student B says that the water must have been 1000g. Who is correct? (1 point) Responses Neither are correct. It would have been 1112g, because there are 2 H2 to 1 O2. Neither are correct. It would have been 1112g, because there are 2 H 2 to 1 O 2 . Student A, because the water was not measured to start with. Student A, because the water was not measured to start with. Student B, because of the law of conservation of matter. Student B, because of the law of conservation of matter. Neither are correct. It was 2000g

Question

Under certain conditions, water can be separated into oxygen and hydrogen gases according to the equation 2H2O → 2H2 + O2. In a lab, 112g of hydrogen gas and 888g of oxygen gas were collected. Student A says that the amount of water to start cannot be determined, but Student B says that the water must have been 1000g. Who is correct? (1 point) Responses Neither are correct. It would have been 1112g, because there are 2 H2 to 1 O2. Neither are correct. It would have been 1112g, because there are 2 H 2 to 1 O 2 . Student A, because the water was not measured to start with. Student A, because the water was not measured to start with. Student B, because of the law of conservation of matter. Student B, because of the law of conservation of matter. Neither are correct. It was 2000g

Answer 1

Neither Student A nor Student B is correct.

Student A is incorrect because the amount of water to start can be determined using stoichiometry. From the balanced equation, it can be determined that 2 moles of water produce 2 moles of hydrogen gas and 1 mole of oxygen gas. The molar mass of water is 18 g/mol, so 2 moles of water would have a mass of 36 g. Therefore, the amount of water to start with would be 36 g.

Student B is also incorrect because the law of conservation of matter states that matter cannot be created or destroyed. In this case, the law states that the total mass of the reactants (water) must be equal to the total mass of the products (hydrogen gas and oxygen gas). Considering that the mass of hydrogen gas collected is 112 g and the mass of oxygen gas collected is 888 g, the total mass of the products is 1000 g. Therefore, the total mass of the water must also be 1000 g.