Do Now - AP - % Comp of a Mixture

Front

What is a pure substance?

Back

A pure substance is a material that has a constant composition and consistent properties throughout. Examples include elements and compounds.

Front

Which of the following is NOT a pure substance: Carbon, Carbon dioxide, Carbon monoxide, Carbonated water?

Back

Carbonated water is NOT a pure substance; it is a mixture.

Front

How do you calculate the percent composition of an element in a compound?

Back

Percent composition = (mass of element in 1 mole of compound / molar mass of compound) x 100%.

Front

Calculate the percent composition of carbon in capsaicin (C_{18}H_{27}NO_3) given the atomic masses: C=12, H=1, N=14, O=16.

Back

Percent composition of C = (18 * 12 / (18*12 + 27*1 + 14 + 3*16)) * 100% = 70.8%.

Front

What is an empirical formula?

Back

An empirical formula is the simplest whole-number ratio of atoms of each element in a compound.

Front

What is a molecular formula?

Back

A molecular formula shows the actual number of atoms of each element in a molecule of a compound.

Front

If 0.105 g of a compound produces 0.257 g of CO2 and 0.0350 g of H2O when burned, how do you find its empirical formula?

Back

Calculate moles of C from CO2 and moles of H from H2O, then find the ratio of moles to determine the empirical formula.

Front

What is the significance of determining the purity of a sample?

Back

Determining purity is essential for ensuring the quality and effectiveness of a substance, especially in chemical reactions.

Front

What information is needed to determine if a sample of MgCl2 is pure?

Back

The mass of Mg and the mass of Cl in the sample are needed to confirm purity.

Front

What is a mole ratio?

Back

A mole ratio is the ratio of the amounts in moles of any two compounds involved in a chemical reaction.