Unit 1 AOS 2 - Quantifying atoms and compounds Quiz (4)

What is the concept of a mole in chemistry?

• A spicy Mexican sauce

• A small animal that burrows underground

• A type of skin blemish

• A unit used to express amounts of a chemical substance

Explain how to calculate the number of moles in a given mass of a substance.

• Add the mass of the substance to its molar mass.

• Divide the mass of the substance by its molar mass.

• Subtract the mass of the substance from its molar mass.

• Multiply the mass of the substance by its molar mass.

What is Avogadro's number and how is it related to the mole concept?

• 6.022 x 10^23; It represents the number of atoms, ions, or molecules in one mole of a substance.

• 6.022 x 10^22; It represents the number of molecules in one mole of a substance.

• 6.022 x 10^23; It represents the number of electrons in one mole of a substance.

• 10^23; It represents the number of protons in one mole of a substance.

If you have 2 moles of a substance, how many atoms or molecules do you have?

• 1.2044 x 10^24 atoms or molecules

• 2 x 10^24 atoms or molecules

• 4.4088 x 10^24 atoms or molecules

• 6.6126 x 10^24 atoms or molecules

How do you calculate the molar mass of a compound?

• Multiply the atomic masses of all the atoms in the compound

• Subtract the atomic masses of all the atoms in the compound

• Add up the atomic masses of all the atoms in the compound.

• Divide the atomic masses of all the atoms in the compound

Calculate the molar mass of water (H2O).

• 18.02 g/mol

• 16.04 g/mol

• 22.99 g/mol

• 20.00 g/mol

What is relative isotopic mass and how is it determined?

• Relative isotopic mass is the mass of an isotope relative to the mass of a hydrogen atom. It is determined by comparing the mass of an isotope to the mass of a helium atom.

• Relative isotopic mass is the mass of an isotope relative to 1/12 the mass of a carbon-12 atom. It is determined by comparing the mass of an isotope to the mass of a carbon-12 atom.

• Relative isotopic mass is the mass of an isotope relative to the mass of a nitrogen atom. It is determined by comparing the mass of an isotope to the mass of a carbon-14 atom.

• Relative isotopic mass is the mass of an isotope relative to the mass of a carbon-14 atom. It is determined by comparing the mass of an isotope to the mass of a carbon-12 atom.

Calculate the relative isotopic mass of an element with 3 isotopes: 25% of mass 10, 50% of mass 11, and 25% of mass 12.

• 12

• 10

• 11

• 13

How is relative atomic mass determined using spectroscopy?

• By analyzing the color of the element in a flame test

• By analyzing the atomic emission or absorption spectra of an element

• By counting the number of protons in the nucleus

• By measuring the density of the element

Explain the process of determining the relative atomic mass of an element using mass spectrometry.

• The relative atomic mass of an element is determined by analyzing the mass spectrum obtained from mass spectrometry.

• The relative atomic mass of an element is determined by measuring the volume of the element in a sample.

• The relative atomic mass of an element is determined by analyzing the color spectrum obtained from mass spectrometry.

• The relative atomic mass of an element is determined by counting the number of atoms in a sample.