Quantative Chemistry

How is the concentration of a solution measured?

In moles per given volume of solution (mol/dm3).

What is the formula to calculate moles of solute in a given volume of known concentration?

moles = concentration x volume (mol = mol/dm3 x dm3).

What happens to concentration with a smaller volume or a larger number of moles of solute?

It gives a higher concentration.

What happens to concentration with a larger volume or a smaller number of moles of solute?

It gives a lower concentration.

What technique is used to measure the volumes of acid and alkali solutions that react?

Titration.

What is the method for performing a titration?

1. Add acid to burette, record initial volume. 2. Add known volume of alkali to conical flask with indicator. 3. Place conical flask on a white tile. 4. Add acid to alkali until the end point is reached. 5. Calculate the volume of acid added (titre). 6. Repeat to get concordant titres.

How is the volume of a solution of known concentration related to the volume or concentration of another substance?

Use the mole ratio and calculate moles of acid and alkali, then calculate the concentration using the equation concentration = moles/volume.

How can you calculate the concentration of an alkali from a titration?

1. Calculate moles of acid (moles = concentration x volume). 2. Use the mole ratio from the reaction. 3. Calculate the moles of alkali from the mole ratio. 4. Calculate the concentration of the alkali (concentration = moles/volume).

What is the relationship between molar amounts of gases and their volumes at room temperature and pressure?

Equal amounts in mol of gases occupy the same volume under the same conditions of temperature and pressure (e.g., RTP).

What is the volume of 1 mole of any gas at RTP?

24 dm3.

How do you calculate the volume of a gas at RTP?

Volume (dm3) = moles x 24.

What is the equation to calculate the volume of a gas in cm3 at RTP?

Volume (cm3) = moles x 24,000.

How can you use the equation to calculate the volume of gaseous reactants and products?

Multiply the number of moles by 24 (for dm3) or 24,000 (for cm3) to find the volume at RTP.

How do you calculate the volume of a gas in reactions?

Use the molar gas volume at RTP (24 dm3) to calculate the volume of gases involved.

How do you calculate the concentration of a solution?

Concentration = mass of solute ÷ volume of solution.

What happens to concentration with a smaller mass or larger volume?

The concentration becomes smaller.

What happens to concentration with a larger mass or smaller volume?

The concentration becomes larger.

How do you calculate the theoretical amount of a product from a given amount of reactant?

1. Calculate moles of the reactant (moles = mass ÷ molar mass or moles = volume ÷ 24). 2. Use the mole ratio from the balanced equation. 3. Calculate moles of the product. 4. Calculate the mass/volume of the product (mass = moles x molar mass, volume = moles x 24).

How do you calculate the percentage yield of a reaction product?

Percentage yield = (Amount of product produced / Maximum amount of product possible) x 100.

What is the definition of atom economy?

It is a measure of the amount of reactants that become useful products, or the efficiency of a reaction.

How do you calculate the atom economy of a reaction?

Atom economy = (Mr of desired product / sum of Mr of all reactants) x 100.