1. Molarity is to moles of solute over liters of solution as molality
is to
A. molar concentration over molal concentration.
B. moles of solute over kilograms of solvent.
C. molal concentration over molar concentration.
D. moles of solute over moles of solvent.
2. In describing an equilibrium reaction involving hydrogen gas, iodine gas, and hydrogen
iodide gas, all of the statements about equation Q = [HI]2 � [H2] [I2] are true except for
which one?
A. Any solids are omitted from equilibrium expressions.
B. The brackets refer to “concentration of . . . ”
C. Coefficients from the original balanced equation (in this case, 2 HI) become exponents.
D. The products go to the denominator, and the reactants go to the numerator
What are your responses and why or explain exactly what you don't understand. For #1, the definition of M is moles/L soln and for m is it moles/kg solvent.
1. The answer is B. Molality is defined as the moles of solute divided by the kilograms of solvent. It is a measure of concentration that takes into account the mass of the solvent, rather than the volume of the solution.
To calculate molality, you need to know the amount of solute in moles and the mass of the solvent in kilograms. You divide the moles of solute by the kilograms of solvent to get the molality of the solution.
2. The statement that is not true about the equation Q = [HI]2 * [H2] * [I2] is A. Any solids are omitted from equilibrium expressions.
Equilibrium expressions are used to represent the concentrations of reactants and products at equilibrium, and solids are not included in these expressions. This is because the concentration of a solid is constant and does not change during the reaction. Only species that are in the gas or aqueous phase are included in equilibrium expressions.
The brackets in the equation indicate the concentration of the species. Coefficients from the balanced equation become exponents in the equilibrium expression, as shown in the equation Q = [HI]2 * [H2] * [I2]. The products are multiplied together and go in the numerator, while the reactants are also multiplied together and go in the denominator.