Chem 1 Unit 9 Review 2024

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

How do you determine the empirical formula from a molecular formula?

Back

To find the empirical formula, divide the subscripts in the molecular formula by their greatest common divisor.

Front

What is the empirical formula for C6H14?

Back

C3H7

Front

Which of the following is an empirical formula: CH3COOH, C6H12O6, H2O?

Back

H2O

Front

Identify the empirical formula from the following: H2O2, C2H6O12, CaCl2, N2O8.

Back

CaCl2

Front

How do you calculate percent by mass of an element in a compound?

Back

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

Front

What is the percent by mass of fluorine in CaF2 (gram-formula mass = 78 g/mol)?

Back

49%.

Front

Given the percentages: 42.07% Na, 18.89% P, and 39.04% O, how do you find the empirical formula?

Back

Convert percentages to grams, find moles of each element, and simplify the ratio.

Front

What is the empirical formula for 42.07% Na, 18.89% P, and 39.04% O?

Back

Na3PO4.

Front

What is the significance of an empirical formula in chemistry?

Back

It provides the simplest ratio of elements in a compound, which is useful for understanding its composition.