Question

17) Which of the following is TRUE? A) Stoichiometry allows prediction of how much of the reactants are necessary to form given amount of product B) Stoichiometry shows the numerical relationship between chemical quantities in a balanced chemical equation. C) Stoichiometry allows prediction of the amounts of products that form in a chemical reaction based on the amounts of reactants. D) All of the above are true. E) None of the above are true. 16) 18) Diatomi Oy can react with the element magnesium to form magnesium oxide (MO). The balanced chemical equation is:02.2 Mg - 2 Mgo 4 moles of magnesium totally reacted with more than enough Os how many moles of Mo would be expected to form? A) I mole B) 2 moles C) 8 moles D) 4 moles E) not enough information 19) How many moles of the can be made from complete reaction of 3.0 moles of Al? Given: 2 Al-6 HCI--2 AICI; + 3 H2 A) 3 moles B) 3.0 moles C) 9.0 moles D) 4.5 moles E) none of the above 20) 20) Suppose two chemical reactions are linked together in a way that the O2 produced in the first reaction goes on to react completely with Mg to form MgO in the second reaction Reaction one: 2 KCIO3 --307.2KCI Reaction two 2 Mg 02--2 Mgo If you start with 4 moles of KCIO3. how many moles of MgO could eventually form? A) 6 moles B) 4 moles C) 12 moles D) 2 moles E) none of the above 21) How many grams of water are made from the reaction of 16.0 grams of oxygen gas? Given the reaction: 2H2O2 + 2H20 A) 16 B) 9 C) 36 D) 18 E) not enough information A-4

Answer 1

17)

stoichiometric coefficient allow us to predict the mol and mass relation between reactants and product.

So, we can calculate mass of product from given mass of reactant and vice versa.

Answer: D

18)

From balanced equation,

Mol of MgO produced = (2/2)*m mol of Mg reacted

= (2/2)*4 moles

= 4 moles

Answer: D

19)

From balanced equation,

Mol of H2 produced = (3/2)*m mol of Al reacted

= (3/2)*3.0 moles

= 4.5 moles

Answer: D

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