Thermal expansion causes the gas particles inside the ping pong ball to spread apart, putting pressure on the dent and popping back out.
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>
Answer: b) loses.
Explanation: As the pendulum swings back and forth, the balance between the two types of energy changes constantly. At some points in its swing, the pendulum has more kinetic energy. At other points, it has more potential energy. No pendulum can swing forever because the system loses energy on account of friction.
Answer:
Explanation:
Im sorry all i know is that #3 is for sure combustion
Answer:
A. Combustion.
Explanation:
Hello there!
In this case, according to the given information about the shown chemical reaction, whereby liquid pentane reacts with oxygen to produce carbon dioxide and hydrogen (should be water); we can use the attached file to realize this is a A. Combustion reaction as it has CO2 and H2O on the products side from a hydrocarbon fuel.
Regards!