Balancing Chemical Equations and Atoms

The video tutorial explains how to balance a chemical equation involving calcium sulfide and hydrochloric acid. It begins by identifying the reactants and products, then counts the atoms on both sides of the equation. The tutorial demonstrates balancing the equation by adjusting coefficients, ensuring equal numbers of each type of atom on both sides. The final balanced equation is presented, with a note on reporting coefficients.

What are the initial counts of calcium, sulfur, hydrogen, and chlorine atoms on the reactant side of the equation?

• One calcium, two sulfur, one hydrogen, and two chlorine

• Two calcium, two sulfur, two hydrogen, and one chlorine

• Two calcium, one sulfur, two hydrogen, and two chlorine

• One calcium, one sulfur, one hydrogen, and one chlorine

What is the first step taken to balance the equation?

• Adding a coefficient of one in front of calcium sulfide

• Adding a coefficient of one in front of hydrochloric acid

• Adding a coefficient of two in front of calcium sulfide

• Adding a coefficient of two in front of hydrochloric acid

How many hydrogen atoms are there on the product side after balancing?

• One

• Two

• Four

• Three

What is the final balanced equation for the reaction between calcium sulfide and hydrochloric acid?

• CaS + HCl → CaCl2 + H2

• CaS + 2HCl → CaCl2 + H2

• CaS + HCl → CaCl + H2S

• CaS + 2HCl → CaCl2 + H2S

What is the convention for reporting coefficients in a balanced chemical equation?

• Write only coefficients greater than one

• Never write any coefficients

• Always write all coefficients, including ones

• Write coefficients only for reactants

Who is the narrator of the video tutorial?

• Dr. A

• Dr. B

• Dr. C

• Dr. D