Y8/2024CT/CHEM1/HT

What are the three main components of an atom?

• Protons, Neutrons, Positrons

• Electrons, Neutrons, Quarks

• Protons, Neutrons, Electrons

• Protons, Photons, Neutrons

Who proposed the first atomic theory?

• Erwin Schrödinger

• Albert Einstein

• Niels Bohr

• John Dalton

What is the charge of an electron?

• -1.602 x 10^-19 coulombs

• +1.602 x 10^-19 coulombs

• 0 coulombs

• -1.0 coulombs

How do neutrons differ from protons?

• Neutrons and protons have the same mass and charge.

• Neutrons differ from protons in charge (neutrons are neutral, protons are positively charged), mass (neutrons are slightly heavier), and their role in determining atomic identity and stability.

• Neutrons are lighter than protons and determine atomic identity.

• Neutrons are positively charged, while protons are neutral.

Define a mixture in chemistry.

• A mixture is a single substance with uniform properties.

• A mixture is a chemical reaction between two substances.

• A mixture is a combination of two or more substances that retain their individual properties.

• A mixture is a solution that cannot be separated by physical means.

What is the difference between pure and impure substances?

• Pure substances are always liquids; impure substances are always solids.

• Pure substances have a consistent composition; impure substances have varied compositions.

• Pure substances can be mixed with other substances; impure substances cannot.

• Pure substances have a variable composition; impure substances have a consistent composition.

How can you calculate the purity of a substance?

• Purity (%) = (volume of pure substance / total volume of the sample) x 100

• Purity (%) = (total mass of the sample / mass of pure substance) x 100

• Purity (%) = (mass of pure substance / total mass of the sample) x 100

• Purity (%) = (mass of impurities / total mass of the sample) x 100

What happens to the solubility of a solid when temperature increases?

• The solubility of a solid decreases with temperature.

• Temperature has no effect on the solubility of a solid.

• The solubility of a solid generally increases with temperature.

• The solubility of a solid is highest at absolute zero.

What is a solute in a solution?

• A solute is a substance that is dissolved in a solution.

• A solute is a gas that cannot be dissolved.

• A solute is a type of solution.

• A solute is a liquid that holds other substances.

How do you identify solutes in a given solution?

• Solutes can only be identified by their color.

• Solutes are always solid and cannot be liquids or gases.

• Solutes are identified by their ability to dissolve in a solvent and can be separated or tested for properties.

• Solutes do not interact with solvents in any way.