because a postive and negative can be used in. ion
Answer:

Explanation:
1 mole of any substance contains the same number of particles. The particles can vary (atoms, molecules, formula units), but there are always 6.022*10²³ particles. In this case, the particles are formula units of potassium nitrate or KNO₃.
Let's create a ratio.

Since we are trying to find the formula units in 0.250 moles, we multiply by that number.

The units of moles of potassium nitrate cancel.

The denominator of 1 can be ignored, so we can make a simple multiplication problem.


If we round to the nearest tenth, the 0 in the hundredth place tells us to leave the 5 in the tenth place.

0.250 moles of potassium nitrate is approximately equal to 1.5*10²³ formula units of potassium nitrate and choice B is correct.
The higher the energy density of a fuel, the greater the amount of energy it has stored.
<h3>What is the energy density?</h3>
The energy density of a fuel is defined as the amount of energy it possesses per unit volume or per unit weight.
<h3>Characteristics of the energy density</h3>
- It is the amount of energy accumulated in an energy vector per unit volume or mass.
- In general, higher density energy sources and carriers are preferable, as many end uses require concentration of such energy.
- The packaging of energy in liquid hydrocarbons is the one with the highest energy density, that is, the highest energy per volume unit, hence its high use in the transportation sector.
Therefore, we can conclude that in general, fuels, especially low molecular weight fuels, have high energy densities.
Learn more about the energy density here: brainly.com/question/2165966
Answer:
Explanation:
ΔTemp => 35⁰C(108K) increases to 57.9⁰C(330.9L) => increases volume (Charles Law)
Use the Kelvin Temperature values in a ratio that will increase the original volume.
ΔVol = 6.33L(330.9/108.0) => gives a larger volume. Using 108.0/330.9 would give a smaller volume and would be contrary to what the problem is asking.
ΔPress => 342 mmHg increases to 821 mmHg => decreases volume (Boyles Law)
Use the pressure values in a ratio that will decrease the original volume.
ΔPress = 6.33L(342/821) => gives a smaller volume. Using 821/342 would give a larger volume and would be contrary to what the problem is asking.
Now, putting both ΔTemp together with ΔPress => net change in volume. (Combined Gas Law)
ΔVol = 6.33L(330.9/108.0)(342/821) = 8.08L (final volume of gas).
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This problem can also be worked using the combined gas law equation:
P₁V₁/T₁ = P₂V₂/T₂ => V₂ = P₁V₁T₂/T₁P₂
V₂ = [(342mm)(6.33L)(330.9K)]/[(108K)(821mm)] = 8.08L (final volume of gas)