some basic concept of chemistry

What is stoichiometry in chemistry?

• The study of animal behavior in relation to chemical compounds

• The process of extracting metals from their ores

• The study of the properties and behavior of inorganic compounds

• Calculation of reactants and products in chemical reactions

How many significant figures are in the number 0.00345?

• 1

• 2

• 5

• 3

State the laws of chemical combination.

• The laws of chemical combination include the law of conservation of mass, the law of definite proportions, and the law of multiple proportions.

• The law of supply and demand

• The law of gravity

• The law of diminishing returns

Define solution and concentration in chemistry.

• Gas and weight of solute in a given amount of solvent

• Liquid and mass of solute in a given amount of solution

• Homogeneous mixture and amount of solute in a given amount of solvent or solution

• Solid and volume of solute in a given amount of solvent

What is the difference between empirical and molecular formula?

• Empirical formula shows the simplest whole-number ratio of atoms, while molecular formula shows the actual number of each type of atom.

• Empirical formula shows the actual number of each type of atom, while molecular formula shows the simplest whole-number ratio of atoms.

• Empirical formula is always the same as the molecular formula for a compound.

• Empirical formula is used for ionic compounds, while molecular formula is used for covalent compounds.

What is the purpose of stoichiometry in chemical reactions?

• To determine the quantities of reactants and products in a chemical reaction.

• To measure the speed of the reaction

• To calculate the temperature of the reaction

• To determine the color of the products

How do you determine the number of significant figures in a measurement?

• By flipping a coin

• By counting the number of digits from the first non-zero digit from the left to the last digit on the right.

• By checking the weather forecast

• By asking a friend

Explain the law of conservation of mass in chemical reactions.

• The law of conservation of mass only applies to solid substances

• The mass of the products is always greater than the mass of the reactants

• The mass of the reactants decreases in a chemical reaction

• The total mass of the reactants must be equal to the total mass of the products.

How is molarity used to express concentration in a solution?

• By representing the number of moles of solute per liter of solution.

• By counting the number of particles in the solution.

• By measuring the volume of solute per liter of solution.

• By determining the mass of solute per liter of solution.

What are the steps to calculate the empirical formula of a compound?

• Determine the mass of each element, convert to moles, divide by smallest mole value, and round if necessary.

• Mix the elements together and weigh the resulting compound

• Count the number of atoms in the compound

• Subtract the mass of each element from the total mass of the compound