Suppose a student repeats Experiment 1 using strontium instead of magnesium. The student adds 5.55 g of strontium to a crucible, heats the crucible and its contents for several minutes over a Bunsen burner, and records the final mass of the crucible and its contents. Write the balanced chemical equation for this reaction. Include physical states. balanced equation: What mass of product is expected to form in this reaction? Assume all of the strontium reacts. mass of product: 6.0 g

The “Chemistry in Focus” segment The Beetle That Shoots Straight discusses the bombardier beetle and the chemical reaction of the decomposition of hydrogen peroxide. m:math>H2O2(aq)H2O(l)+O2(g) e balanced equation given in the segment is m:math>2H2O2(aq)2H2O(l)+O2(g) y can’t we balance the equation in the following way? m:math>H2O2(aq)H2(g)+O2(g) e molecular-level pictures like those in Section 6.3 to support your answer.

4.64 Using the web, find information about the amount of lead in the environment during the past 50 years. Correlate what you observe with the presence or absence of tetraethyl lead in gasoline.

What does it mean to say an equation is balanced? Why is it important for an equation to be balanced?

Many over-the-counter antacid tablets are now formulated using calcium carbonate as the active ingredient, which enables such tablets to also be used as dietary calcium supplements. As an antacid for gastric hyperacidity, calcium carbonate reacts by combining with hydrochloric acid found in the stomach, producing a solution of calcium chloride, converting the stomach acid to water, and releasing carbon dioxide gas (which the person suffering from stomach problems may feel as a “burp”). Write the unbalanced chemical equation for this process.