Cite the evidence that indicates that only physical changes occur when a platinum wire is heated in a Bunsen burner flame.

Describe the difference between a chemical change and a physical change. What are three examples of physical changes?What are three signs that a chemical change has taken place?How does temperature affect chemical changes?

What evidence of chemical change is visible when electricity is run through water?

Calculate the boiling point of acetic acid in
(a) kelvins
(b) degrees Fahrenheit

Are there more atoms of silicon or hydrogen in the Earth's crust, seawater, and atmosphere? Use Table and the fact that the mass of a silicon atom is about 28 times that of a hydrogen atom.

A sample of iron was heated to $125.0^{\circ}\mathrm{C}$, then placed into $375\mathrm{~g}$ of water at $19.8^{\circ}\mathrm{C}$. The temperature of the water rose to $25.6^{\circ} \mathrm{C}$. How many grams of iron were in the sample?

Of the ten most abundant elements in the Earth's crust, seawater, and atmosphere, how many are metals? nonmetals? metalloids?

Under what conditions does a precipitate form in a chemical reaction?

$4.50\mathrm{ft}$ is how many centimeters?

(a) $11.4$
(b) $21.3$
(c) $454$
(d) $137$

Complete the following metric conversions using the correct number of significant figures:

(a) $28.0\mathrm{~cm}$ to $\mathrm{m}$
(b) $1000 .\mathrm{m}$ to $\mathrm{km}$
(c) $9.28\mathrm{~cm}$ to $\mathrm{mm}$
(d) $10.68\mathrm{~g}$ to $\mathrm{mg}$
(e) $6.8\times 10^4\mathrm{mg}$ to $\mathrm{kg}$
(f) $8.54\mathrm{~g}$ to $\mathrm{kg}$
(g) $25.0\mathrm{~mL}$ to $\mathrm{L}$
(h) $22.4\mathrm{~L}$ to $\mu\mathrm{L}$

Julius decided to heat $75 \mathrm{~g} \mathrm{CaCO}$ to determine how much carbon dioxide is produced. He collected the carbon dioxide in a balloon. Julius found the mass of the $\mathrm{CaO}$ remaining was $42 \mathrm{~g}$. If $44 \mathrm{~g}$ of carbon dioxide take up $24 \mathrm{dm}^3$ of space, how many liters of gas were trapped in the balloon?

Which of the following is a mixture?

(a) water
(b) iron(II) oxide
(c) sugar solution
(d) iodine

If $40.0 \mathrm{~kJ}$ of energy are absorbed by $500.0 \mathrm{~g}$ of water at $10.0^{\circ} \mathrm{C}$, what is the final temperature of the water?

Using several of the key terms given in this chapter, create a crossword puzzle.