Week 9 Day 2 Science

Which types of subatomic particles are found inside the nucleus of an atom?

• A. protons with a positive charge and neutrons with a neutral charge

• B. protons with a neutral charge and neutrons with a negative charge

• C. electrons with a negative charge and neutrons with a neutral charge

• D. electrons with a positive charge and neutrons with a negative charge

Nitrogen naturally exists as a diatomic molecule . Which chemical formula represents a nitrogen molecule?

• A. N

• B. Nn

• C. N₂

• D. 2N

A student makes models to show the arrangement of atoms in elements, compounds, and mixtures. The student uses three different types of marbles in the models X. Y, and Z.

• A. X: element;

  Y: compound; Z: mixture

• B. X: element;

  Y: mixture;

  Z: compound

• C. X: compound;

  Y: element;

  Z: mixture

• D. X: mixture;

  Y: element;

  Z: compound

A student adds a strip of aluminum (Al) to a solution of sulfuric acid (H₂ SO₄). The student writes the chemical equation with the amounts of reactants used and the expected amounts of products.

The student only collects 3 g of hydrogen gas (H₂ ). What is the best explanation for the amount of gas collected?

• A. The number of atoms of the products and reactants changed during the reaction.

• B. The particles in hydrogen gas are spread far apart and move quickly.

• C. The system was not completely closed, and some hydrogen gas escaped.

• D. The mass of the products does not need to equal the mass of the reactants.

Which is a chemical property of matter?

• A. color

• B. density

• C. flammability

• D. size