Periodic table and conservation

If a student is chemically combining 4 g of hydrogen with 2 g of oxygen, what will be the mass of the product?

• 4g

• 6g

• 8g

• 10g

When 15 grams of zinc are combined with 20 grams of hydrochloric acid, two new products are created. What will be the combined weight of the products?

• 5 grams

• 15 grams

• 20 grams

• 35 grams

When vinegar and baking soda are combined, a mixture is produced, and a gas is released. Which statement is true?

• The mass of the gas is equal to the mass of the vinegar and baking soda.

• The mass of the gas is greater than the mass of the vinegar and baking soda

• The mass of the mixture and gas is equal to the mass of the vinegar and baking soda.

• The mass of the mixture and gas is greater than the mass of the vinegar and baking soda.

Which is true of mass during a chemical reaction?

• Mass increases.

• Mass decreases

• Mass remains the same

• Mass depends on the chemicals involved.

Which of these is one similarity of the elements in the first group of the periodic table?

• The elements in the group have similar atomic masses.

• The elements in the group have the same number of electrons

• The elements in the group are very unreactive metals

• The elements in the group react with oxygen in similar ways

Which ratio of reactants to products supports the law of conservation of mass?

• 2:1 because the mass of the reactants is halved during the reaction

• 1:2 because the mass of the reactants is doubled during the reaction

• 1:1 because the mass of the reactants before the reaction is equal to the mass of the products after the reaction

• 1:0 because the mass of the reactants is completely used up during the reaction so the products have no mass after the reaction

How are elements similar to those in the same group on the periodic table?

• They have the same number of valence electrons

• They have the same number of electrons

• They have the same number of protons

• They have the same atomic mass

Which statement best explains how periods on the periodic table are organized?

• increasing atomic number from left to right

• increasing number of neutrons from left to right

• decreasing number of electrons from left to right

• decreasing atomic mass number from left to right

Which pair of elements has the most similar properties?

• Li and B

• I and Ca

• K and He

• N and P

Which is true of a chemical equation?

• Products and reactants must be balanced.

• Subscripts must be used with all products and reactants

• Energy must be included in the beginning of the reaction

• Coefficients must be used with all products and reactants