Your class is discussing the difference between scientific theories and personal beliefs. Write a brief paragraph explaining why the Big Bang concept is considered a theory rather than a belief or an opinion.

You have seen photos of small objects floating in the air inside the International Space Station. Some people say these objects are weightless. Does this mean the objects have no weight? Explain your answer.

Write a short answer to each of these questions. How are electrical systems useful in body functions?

The copper(I) ion forms a complex ion with $C N^{-}$ according to the following equation:

$$\mathrm{Cu}^{+}(a q)+3 \mathrm{CN}^{-}(a q) \rightleftharpoons \mathrm{Cu}(\mathrm{CN})_{3}^{2-}(a q) \quad K=1.0 \times 10^{11}$$

Calculate the solubility of $\mathrm{CuBr}(s)\left(K_{\mathrm{sp}}=1.0 \times 10^{-5}\right)$ in 1.0 L of 1.0 M NaCN.

Factor each polynomial over the set of rational number coefficients. $81 y^{2}-\frac{1}{49}$

Assume that Samsung (Samsung.com) is considering offering a service similar to Apple’s iTunes music download store. However, instead of developing the division internally, Samsung is considering buying a company that already offers such services. Would absorption or variable costing be most useful to Samsung in evaluating whether to acquire an existing business that provides services similar to iTunes? Explain.

Copy each of the following statements into your notebook. Fill in the blanks with a word or phrase that correctly completes the sentence. During our ____________ season, Earth's northern hemisphere is tilted toward the Sun to a greater degree than it is at other times of the year.

A radio-wave transmitter and a receiver separated by a distance d and both a distance h above the ground. The receiver can receive signals both directly from the transmitter and indirectly from signals that reflect from the ground. Assume the ground is level between the transmitter and receiver and a $180^{\circ}$ phase shift occurs upon reflection. Determine the longest wavelengths that interfere (a) constructively and (b) destructively.

Ethene is converted to ethane by the reaction $\mathrm{C}_{2} \mathrm{H}_{4}(g)+\mathrm{H}_{2}(g) \stackrel{\text { Catallyst }}{\longrightarrow} \mathrm{C}_{2} \mathrm{H}_{6}(g)$ $C_{2} H_{4}$ flows into a catalytic reactor at 25.0 atm and $300^{\circ} \mathrm{C}$ with a flow rate of 1000 L/min. Hydrogen at 25.0 atm and $300^{\circ} \mathrm{C}$ flows into the reactor at a flow rate of 1500. L/min. If 15.0 kg $\mathrm{C}_{2} \mathrm{H}_{6}$ is collected per minute, what is the percent yield of the reaction?

Google uses variable costing for several business decisions. How can variable costing income statements be converted to absorption costing?

How do you know if a new substance was formed from old substances being mixed together?

Find each of the following in rectangular form $x+iy$ and check your results by computer. Remember to save time by doing as much as you can in your head. $e^{3 \ln 2-i \pi}$

Show how each of the following strong electrolytes “breaks up” into its component ions upon dissolving in water by drawing molecular-level pictures. $\mathrm{KMnO}_{4}$

A basketball player succeeds in making a basket 3 tries out of 4. How many tries are necessary in order to have probability > 0.99 of at least one basket?