The abundance of iodine in seawater is $5.0 \times 10^{-8}\%$ by mass. How many kilograms of seawater must be treated to obtain $1.0\mathrm{~g}$ iodine ?

What percent of the first 36 elements on the periodic table are solids at room temperature?

Classify each of the following as a homogeneous mixture or heterogeneous mixture: (3.1) a. lemon-flavored water b. stuffed mushrooms c. eye drops

What is the correct IUPAC name for Ca(NO3)2?

Write formulas for the Ionic compounds formed by the following ions. Use units as a guide to your solutions. aluminum and bromide

Make the following conversions using the correct number of significant figures:

(a) $35.6\mathrm{~m}$ to $\mathrm{ft}$
(b) $16.5\mathrm{~km}$ to $\mathrm{mi}$
(c) $4.5$ in. $^3$ to $\mathrm{mm}^3$
(d) $95\mathrm{lb}$ to $\mathrm{g}$
(e) $20.0\mathrm{~gal}$ to $\mathrm{L}$
(f) $4.5\times 10^4 \mathrm{ft}^3$ to $\mathrm{m}^3$

Evaluate each of the following expressions. State the answer to the proper number of significant figures:

(a) $15.2-2.75+15.67$
(b) $(4.68)(12.5)$
(c) $\frac{182.6}{4.6}$
(d) $1986+23.84+0.012$
(e) $\frac{29.3}{(284)(415)}$
(f) $\left(2.92 \times 10^{-3}\right)\left(6.14 \times 10^5\right)$

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

What does the symbol of an element stand for?

Silver nitrate has a lattice energy of - 820 kJ/ mol and a heat of solution of 22.6 kJ/ mol. Calculate the heat of hydration for silver nitrate.

Is there a pattern to the location of the gaseous elements on the periodic table? If so, describe it.

What elements are present in each compound?

(a) magnesium bromide $\mathrm{MgBr}_2$
(b) carbon tetrachloride $\mathrm{CCl}_4$
(c) nitric acid $\mathrm{HNO}_3$
(d) barium sulfate $\mathrm{BaSO}_4$
(e) aluminum phosphate $\mathrm{AlPO}_4$

Write formulas for the following compounds that a colleague read to you:

(a) $\mathrm{NA}-\mathrm{CL}$
(b) $\mathrm{H} 2-\mathrm{S}-\mathrm{O} 4$
(c) $\mathrm{K2-O}$
(d) $\mathrm{Fe} 2-\mathrm{S} 3$
(e) $\mathrm{K} 3-\mathrm{P}-\mathrm{O} 4$
(f) $\mathrm{CA}$ (pause) $\mathrm{CN}$ taken twice
(g) $\mathrm{C} 6-\mathrm{H} 12-\mathrm{O} 6$
(h) $\mathrm{C} 2-\mathrm{H} 5$ (pause) $\mathrm{OH}$
(i) $\mathrm{CR}$ (pause) $\mathrm{NO3}$ taken three times

These formulas look similar but represent different things.

$$8 \mathrm{~S} \quad \mathrm{~S}_8$$

Compare and contrast them. How are they alike? How are they different?