Question :
11.Which symbol, often found in chemical equations, indicates that a : 1318385
11.Which symbol, often found in chemical equations, indicates that a substance is dissolved in water?
A) (w)
B) (l)
C) (aq)
D) (d)
E) ?
12.Consider the two beakers labeled A and B. Beaker A contains 1 mole of iron atoms, and Beaker B contains 1 mole of lead atoms. Which statement concerning these samples is known with certainty?
A) Beakers A and B contain an equal number of atoms.
B) Beakers A and B contain equal masses of atoms.
C) Beakers A and B contain an equal volume of atoms.
D) Beakers A and B contain samples with the same density.
E) None of the above is known with certainty.
13.The chemical equation below is unbalanced. What is the coefficient of water when the equation is balanced?
Mg(OH)2(s) + HCl(g) ? MgCl2(s) + H2O(l)
A) 1
B) 2
C) 3
D) 4
E) No coefficient would be shown.
14.Aluminum metal and oxygen gas are produced when aluminum oxide is heated at high temperature. Which statement concerning this chemical change is true?
A) Aluminum oxide is the product in this reaction.
B) This reaction is a combustion reaction.
C) Aluminum and oxygen are the reactants in this reaction.
D) This reaction is a decomposition reaction.
15.The unbalanced equation for the combustion of octane, a component of gasoline, is shown below. What would be the coefficient of carbon dioxide once the equation is balanced?
C8H18(l) + O2(g) ? CO2(g) + H2O(l)
A) 2
B) 25
C) 16
D) 18
E) No coefficient would be shown.
16.The chemical equation below is not balanced. Balance the equation, then determine which statement concerning the balanced equation is true.
KClO3(s) ? KCl(s) + O2(g)
A) The balanced equation will have an equal number of moles of reactants and products.
B) The balanced equation will have three atoms of oxygen on each side.
C) The balanced equation will have one atom of potassium on each side.
D) The balanced equation will have two atoms of chlorine on each side.
E) The balanced equation will contain a substance whose coefficient is 1.
17.Consider the chemical equation shown below. How many moles of oxygen gas are needed to react with hydrogen to form one mole of water?
2H2(g) + O2(g) ? 2H2O(l)
A) 0.5 mol
B) 1 mol
C) 3 mol
D) 4 mol
E) 5 mol
18.Hydrogen fluoride will react with glass (silicon dioxide, SiO2) according to the equation below. What mass of HF is required to react completely with 16.0 g of glass? [Molar masses: Si, 28.09 g/mol; F, 19.00 g/mol; H, 1.01 g/mol; O, 16.00 g/mol]
4HF(g) + SiO2(s) ? SiF4(g) + 2H2O(g)
A) 5.33 g
B) 21.3 g
C) 64.0 g
D) 80.0 g
E) 320 g
19.Glucose (C6H12O6) is an important energy-rich compound, produced by photosynthesis according to the equation below. What mass of glucose can be produced from 2.61 mol of CO2 and the necessary water? [Molar masses: C, 12.01 g/mol; H, 1.01 g/mol; O, 16.00 g/mol]
6CO2(g) + 6H2O(l) ? C6H12O6(l) + 6O2(g)
A) 0.0128 g
B) 0.0869 g
C) 69.0 g
D) 78.4 g
E) 414 g
20.Upon mixing a clear colorless BaCl2 solution with a clear, colorless Na2SO4 solution according to the reaction below, a student observes a white cloudiness form. What is responsible for the cloudiness that is observed?
BaCl2(aq) + Na2SO4(aq) ? BaSO4(s) + 2NaCl(aq)
A) NaCl
B) BaSO4
C) BaCl2
D) Na2SO4
E) It is impossible to tell without doing the reaction oneself.
