Exam Review Chemistry Sem 2 24-25

Front

What is the formula to calculate the % composition by mass of an element in a compound?

Back

% Composition = (Mass of Element / Mass of Compound) x 100

Front

How many moles are in 6.02 x 10^23 molecules of a substance?

Back

1 mole (Avogadro's number states that 6.02 x 10^23 molecules equals 1 mole).

Front

What is the chemical formula for Tin (II) phosphate?

Back

Sn3(PO4)2

Front

What is the mass of 5.00 x 10^23 atoms of oxygen?

Back

13.3 g (Using the molar mass of oxygen and Avogadro's number).

Front

What is the term for converting a quantity from one unit to another?

Back

Dimensional analysis

Front

Define Avogadro's number.

Back

Avogadro's number is 6.02 x 10^23, which is the number of particles in one mole of a substance.

Front

What is the molar mass of CO2?

Back

The molar mass of CO2 is approximately 44.01 g/mol.

Front

What does STP stand for in chemistry?

Back

Standard Temperature and Pressure (0°C and 1 atm).

Front

What is the difference between empirical and molecular formulas?

Back

Empirical formula shows the simplest ratio of elements, while molecular formula shows the actual number of atoms in a molecule.

Front

How do you calculate the number of moles from grams?

Back

Number of moles = Mass (g) / Molar mass (g/mol).