How many significant figures does each of the following quantities have? Explain your answers. (a) $76.600 \mathrm{~kJ}$ (b) $4.50200 \times 10^3 \mathrm{~g}$ (c) $3000 \mathrm{~nm}$ (d) $0.00300 \mathrm{~mL}$ (e) 18 students (f) $3 \times 10^{-5} \mathrm{~g}$ (g) $47.60 \mathrm{~mL}$ (h) $2070 \mathrm{mi}$

A Big Mac hamburger from McDonald's contains 540 Calories. (a) How many kilojoules does a Big Mac contain? (b) For how many hours could the amount of energy in a Big Mac light a 100 watt lightbulb? $(1$ watt $=1 \mathrm{~J} / \mathrm{s})$

What SI units are used for measuring the following quantities? For derived units, express your answers in terms of the six fundamental units. (a) Mass (b) Length (c) Temperature (d) Volume (e) Energy (f) Density

The distance from Earth to the Sun averages about 150,000,000 km. This makes the distance between the Sun and Earth about 110 times larger than the diameter of the Sun (150 ,000,000/1,392,000 = 110). If you were to use a 1-foot (12-inch) basketball to represent the Sun, how far would it have to be from Earth to be an accurate scale model? a) 1 foot, b) 10 feet, c) 30 feet , d) 110 feet , e) 300 feet.

A calibrated flask was filled to the $25.00 \mathrm{~mL}$ mark with ethyl alcohol By weighing the flask before and after adding the alcohol, it was determined that the flask contained $19.7325 \mathrm{~g}$ of alcohol. In a second experiment, $25.0920 \mathrm{~g}$ of metal beads were added to the flask, and the flask was again filled to the $25.00 \mathrm{~mL}$ mark with ethyl alcohol. The total mass of the metal plus alcohol in the flask was determined to be $38.4704 \mathrm{~g}$. What is the density of the metal in $\mathrm{g} / \mathrm{mL}$ ?

A $125 \mathrm{~mL}$ sample of water at $293.2 \mathrm{~K}$ was heated for $8 \mathrm{~min}$, $25 \mathrm{~s}$ so as to give a constant temperature increase of $3.0^{\circ} \mathrm{F} / \mathrm{min}$. What is the final temperature of the water in degrees Celsius?

An Eastern diamondback rattlesnake was milked until $0.134 \mathrm{~g}$ of venom was obtained. The venom was then administered subcutaneously in equal portions to 550 mice with an average weight of $0.70 \mathrm{oz}$, and exactly half the mice died. What is the LD $\mathrm{so}^{\text {(in }} \mathrm{g} / \mathrm{kg}$ ) for the snake venom in mice? See the FYI at the end of this chapter.

Which of the following statements are correct? Explain your answers.
A. Gap junctions connect the cytoskeleton of one cell to that of a neighboring cell or to the extracellular matrix.
B. A wilted plant leaf can be likened to a deflated bicycle tire.
C. Because of their rigid structure, proteoglycans can withstand a large amount of compressive force.
D. The basal lamina is a specialized layer of extracellular matrix to which sheets of epithelial cells are attached.
E. Epidermal cells in the skin are continually shed and are renewed every few weeks; for a tattoo to be long-lasting, it is therefore necessary to deposit pigment below the epidermis.
F. Although stem cells are not differentiated, they are specialized in the sense that they give rise only to specific cell types.

The $\mathrm{LD}_{50}$ of aspirin in rats is given in the FYI at the end of this chapter. If a baby aspirin tablet contains $81 \mathrm{mg}$ of aspirin, how many whole tablets would a $0.75 \mathrm{lb}$ rat have to consume to have at least a $50 \%$ chance of dying from the dose?

Imagine that you place a cork measuring $1.30 \mathrm{~cm} \times 5.60 \mathrm{~cm} \times$ $3.00 \mathrm{~cm}$ in a pan of water and that on top of the cork you place a small cube of lead measuring $1.15 \mathrm{~cm}$ on each edge. The density of cork is $0.235 \mathrm{~g} / \mathrm{cm}^3$, and the density of lead is $11.35 \mathrm{~g} / \mathrm{cm}^3$. Will the combination of cork plus lead float or sink?

At a certain point, the Celsius and Fahrenheit scales "cross," giving the same numerical value on both. At what temperature does this crossover occur?

Vinaigrette salad dressing consists mainly of olive oil and vinegar. The density of olive oil is $0.918 \mathrm{~g}^{\mathrm{g} / \mathrm{cm}^3}$, the density of vinegar is $1.006 \mathrm{~g}^2 \mathrm{~cm}^3$, and the two do not mix. If a certain mixture of olive oil and vinegar has a total mass of $397.8 \mathrm{~g}$ and a total volume of $422.8 \mathrm{~cm}^3$, what is the volume of oil and what is the volume of vinegar in the mixture?

A bag of Hershey's Kisses contains the following information: Serving size: 9 pieces $=41$ grams Calories per serving: 230 Total fat per serving: $13 \mathrm{~g}$ (a) The bag contains $2.0 \mathrm{lbs}$ of Hershey's Kisses. How many Kisses are in the bag? (b) The density of a Hershey's Kiss is $1.4 \mathrm{~g} / \mathrm{mL}$. What is the wolume of a single Hershey's Kiss? (c) How many Calories are in one Hershey's Kiss? (d) Each gram of fat yields 9 Calories when metabolized. What percent of the Calories in Hershey's Kisses are derived from fat?

A $1.0$ ounce piece of chocolate contains $15 \mathrm{mg}$ of caffeine, and a $6.0$ ounce cup of regular coffee contains $105 \mathrm{mg}$ of caffeine. How much chocolate would you have to consume to get as much caffeine as you would from $2.0$ cups of coffee?