Answer: 
Explanation: Because barium is in Group 2, it forms ions with a charge of +2. Fluorine, in Group 17, form ions with a charge of -1. Cross the charges to get the subscripts (Since Ba has a charge of +2, F has a subscript of 2. Because F has a charge of -1, Ba needs a subscript of 1). Therefore, a formula unit of the compound is .
Below are the choices:
<span>The independent variable is the number of dry cells, and the dependent variable is the length of time the bulb works.
</span><span>The independent variable is the length of time the bulb works, and the dependent variable is the number of dry cells.
</span><span>The independent variable is the number of dry cells, and the dependent variable is the amount of energy available.
</span><span>The independent variable is the amount of energy available, and the dependent variable is the number of dry cells.
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I think the answer is <span>The independent variable is the number of dry cells, and the dependent variable is the amount of energy available.</span>
Answer:
<em>The grams of hydrogen gas that are released is 0.343 gram</em>
Explanation:
<em>Given that:</em>
<em>2 Na + 2h₂0 ⇒ 2Na0H +N₂</em>
<em>Molecules of Na = 7.9/2.3 = 0.343 mol Na</em>
<em>Now,</em>
<em>2 molecules of Na produces one mole h₂</em>
<em>0.343 mol of Na produce 0.343/2 = 0.1717 mol h₂</em>
<em>h2 = molecules * mw (molecular weight) =0.1717 * 2 =0.343 grams</em>
<em>Therefore the grams of hydrogen gas released is = 0.343 grams</em>
