Chapter 13 Summary

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CHAPTER 13

Toxic Changes

SUMMARY

KEY TERMS

physical change

coefficient

formula unit

combination reaction

decomposition reaction

single exchange reaction (single replacement)

double exchange reaction (double replacement)

Toxins Update

A toxic substance causes an undesirable chemical reaction, producing a harmful or unhealthy change in a living system. Chemical equations keep track of these changes and allow you to predict what you will observe when compounds combine. Becoming familiar with chemical equations is the first step in understanding these chemical changes.

REVIEW EXERCISES

Question 13.1

1. Why is it difficult to identify a physical or chemical change through observations alone?

Question 13.2

2. Based on the chemical equation for a reaction, can you tell if any of the substances are toxic?

Question 13.3

3. Consider the equation for the formation of a kidney stone.

Na3PO4(aq) + 3CaCl2(aq) → Ca3(PO4)2(s) + 6NaCl(aq)

  1. Is each reactant bonded ionically or covalently? How do you know?

  2. Is this is a combination reaction, decomposition reaction, single exchange reaction, or double exchange reaction?

  3. Is this a chemical change or a physical change?

  4. How does a balanced reaction show that matter is conserved?

  5. What is the chemical name of the solid that makes up a kidney stone?

Question 13.4

4. Copy and balance these chemical equations.

  1. N2(g) + H2(g) → N2H4(g)

  2. KNO3(s) + K(s) → K2O(s) + N2(g)

  3. H2SO4(aq) + NaCN(aq) → HCN(g) + Na2SO4(aq)

  4. H3PO4(aq) + Ca(OH)2(aq) → Ca3(PO4)2(aq) + H2O(l)

  5. C3H8(g) + O2(g) → CO2(g) + H2O(l)

  6. H2S(g) + O2(g) → SO2(g) + H2O(l)

  7. H2(g) + O2(g) → H2O(l)