When grapes become fermented, they turn into wine.
When you add a pinch of baking soda into vinegar, carbon dioxide gas is produced
Sugar burns and turns black. A completely new substance was formed, which is the main pointer for it being a chemical reaction. More evidence would be change of color, odor, and the fact that flammability is a chemical property so setting something on fire would be a chemical change.
Answer:

Explanation:
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In this case, according to the given information, it turns out possible for us to calculate the final pressure by using the Boyle's law as an inversely proportional relationship in pressure to volume at constant temperature:

Thus, we solve for our target, P2, to obtain:

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Answer:

Explanation:
When converting from moles to atoms, we must use Avogadro's number. This number tells us there are 6.022 * 10²³ atoms in 1 mole. We can multiply this number by the number of moles.
First, we must set up Avogadro's number as a ratio.

Next, multiply the number of moles by the ratio.

When we multiply, the moles of silicon will cancel.

Since the denominator of the fraction is 1, we can cancel it out too.


The original measurement (2.5 moles) has 2 significant figures (2 and 5). Therefore we must round to 2 sig figs. For this question, 2 sig figs is the tenth place.
The 0 in the hundredth place tells us to leave the 5 in the tenth place.

There are about <u>1.5 * 10²⁴ atoms of silicon.</u>