When solving for concentration, you divided mass by:

1.)weight

2.)volume

3.)distance

Volume.

Explanation:

Concentration is defined as the ratio between the amount of substance in terms of mass units or moles and the volume or mass of a solution. There are many ways to look at it.

1. Molarity: it's the measure of concentration expressed as moles of solute divided by the volume of the solution in liters (mol/L units, or M);

2. Molality: the measure of concentration expressed as moles of solute divided by the mass of solvent in kilograms (mol/kg units, or m);

3. Percent mass: the measure of concentration expressed as mass of the component divided by the total mass of the mixture (%w/w, or simply %);

4. Percent volume: similar to percent mass, but in this case we divide the volume of the component by the volume of the mixture (%V/V);

5. Mole fraction: this is the ratio between the moles of component and the total moles of all the components present in the mixture (dimensionless, but might be expressed as percentage if needed).

As you can see, concentration can be expressed very differently. What unites all of these concepts is the fact that we're looking at a fraction of the solute/component with respect to the total mass/volume of the solution or the mixture.

Typically, we're interested in molarity, as it's used most often, that is, the ratio between the moles and volume. Remembering that moles is directly proportional to mass (moles are equal to mass divided by molar mass), we may also measure concentration as mass/volume fraction instead of moles/volume.

the correct answer is b. a strong acid completely dissociates to its ions when dissolved in water. completely dissociates to and ions. a is incorrect because does not fully ionize to and ions and some remain as the compound . c and d are incorrect because, and do not fall into the category of bronsted lowry acids. a bronsted lowry acid is a proton donor and since both molecules do not have a proton to donate they are not bronsted lowry acids. likewise,   if we use the lewis acid definition, they cannot be acids. a lewis acid is an electron pair acceptor. both and have a complete octet so can not accept any electrons which disqualifies them as acids.