Describe two reasons for balancing chemical equations.

Describe the steps to balancing a chemical equation.

Balancing Chemical Equations Write the balanced chemical equation for the reaction in which methane, $CH_4$, reacts with oxygen gas to produce water and carbon dioxide.

What strategy for balancing chemical equations did you find particularly useful? Share this strategy with a classmate who is having difficulty with balancing equations,

You are experimenting with a radioactive sample of polonium. At the end of 14.0 minutes, exactly 1/16 of the polonium remains. What is the corresponding half life (T sub 1/2) of polonium?

How do city planners use a geographic information system?

Do you think that all of today's developing nations will complete the demographic transition? Why or why not?

The smallest living structure is the ______ .

An 18-foot pole casts a 5-foot shadow. Jacob, who is 6 feet tall, stands next to the pole. How long is his shadow?

Estimate the answers to these calculations. a.

$$\begin{array}{llll}{298 \times 10.75} & {\text { b. } 3.8^{2}} & {\text { c. } \frac{147}{11.02}} & {\text { d. } \sqrt{103}}\end{array}$$

What are the major economic activities in India?

Write answers with only positive exponents. Assume that all variables represent nonzero real numbers. $\frac{(3 r)^{2} r^{4}}{r^{-2} r^{-3}}\left(9 r^{-3}\right)^{-2}$

Unlike the elements in groups 1A and 2A, those in group 3A do not show a regular decrease in first ionization energy as you move down the column. Explain the irregularities.

Consider the reaction

$$2 \mathrm { HCl } ( a q ) + \mathrm { Ba } ( \mathrm { OH } ) _ { 2 } ( a q ) \longrightarrow \mathrm { BaCl } _ { 2 } ( a q ) + 2 \mathrm { H } _ { 2 } \mathrm { O } ( l )\quad \Delta H = - 118\ \mathrm { kJ }$$

Calculate the heat when 100.0 ml of 0.500 M HCl is mixed with 300 .0 mL of 0.100 M $\mathrm { Ba } ( \mathrm { OH } ) _ { 2 }.$ Assuming that the temperature of both solutions was initially $25^\circ C$ and that the final mixture has a mass of 400.0 g and a specific heat capacity of $4.18\ \mathrm { J } \mathrm { C } ^ { - 1 } \mathrm { g } ^ { -1},$ calculate the final temperature of the mixture.