CHEMISTRY -SEM 1-FINAL 2024

Front

What is the percentage of oxygen in H2O?

Back

H2O has a percentage of oxygen of approximately 88.79%.

Front

What is the empirical formula for a compound with 1.2% H, 42.0% Cl, and 56.8% O?

Back

The empirical formula is HClO3.

Front

How do you calculate the percent composition of a compound?

Back

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

Front

What is the percent composition of Cu2S?

Back

%Cu = 79.854%, %S = 20.145%.

Front

What does the electron configuration 1s2 2s2 2p6 3s2 represent?

Back

It represents the element magnesium.

Front

What are isotopes?

Back

Isotopes are atoms of the same element with different numbers of neutrons.

Front

Which two isotopes of the same element are represented by I. 77_35X and IV. 81_35X?

Back

They are isotopes of the same element X.

Front

What is the molar mass of H2O?

Back

The molar mass of H2O is approximately 18.02 g/mol.

Front

Define empirical formula.

Back

An empirical formula is the simplest whole-number ratio of elements in a compound.

Front

What is the significance of the atomic number?

Back

The atomic number represents the number of protons in an atom and defines the element.