Chapter 1 : Matter

what is unit for Molarity ?

• g/mL

• m

• mol/kg

• mol/L

Choose the correct formula for Molality

• mole of solvent / mass of solvent (kg)

• mole of solute / mass of solvent (g)

• mole of solute / mass of solvent (kg)

what is solvent ?

• The substance present in a smaller amount in a solution

• The substance present in a larger amount in a solution

• A homogeneous mixture formed when an amount of solute dissolve

  completely in a solvent

Define the empirical formula

• Chemical formula that shows the simplest ratio of atoms of the

  elements present in a compound.

• Chemical formula that shows the actual number of atoms of each

  element in a molecule.

what is mole fraction of NaCl in a solution prepared by dissolving 0.25 mol NaCl in 50 mol H20

• 0.005

• 0.05

• 200

Determine the molarity of 93 ml methanol solutions that contains 1.92 g of methanol, CH3OH

• 0.065

• 0.65

• 48.44

What device is used to determine the relative atomic mass and the relative abundance of isotopes?

• Chromatograph

• Calorimeter

• The mass spectrometer.

• Spectrophotometer

What is the definition of an isotope?

• Isotopes are two or more atoms of the same element with the different number of protons in the nucleus and also have different number of neutrons

• Isotopes are two or more atoms of the same element with the different number of protons in the nucleus but have same number of neutrons.

• Isotopes are two or more atoms of the same element with the same number of protons in the nucleus but a different number of neutrons. They have the same chemical properties but different physical properties​.

How do you calculate the number of neutrons in an atom?

• Number of Neutrons = nucleon number - proton number

• Number of Neutron = Mass Number - nucleon number

• Number of Neutrons = Mass Number - nucleon number

The number of protons is equal to

• the energy level

• the atomic number

• the number of neutrons

• the periodic table groups