Answer:
The correct answer is - 3.012×10^23 molecules
Explanation:
The number of molecules is present in any mole of an element or compound are the same. To find the molecules you need to multiply the number of the moles of the compound by Avogadro's number:
Moles are calculated from the molecular weight, for AlF3
= 26.98 + 3×19
= 26.98 + 57
= 83.98
Then moles in 42 grams:
= 42/83.98
= 0.5001190 moles
Now the number of molecules = moles*Avogadro's number
= 0.500110×6.022×10^23
= 3.011×10^23 molecules
Answer:
- <u>25.0 liter of nitrogen gas</u>
Explanation:
<u>1. Chemical equation</u>
Ammonium nitrite is a solid compound that decomposes into nitrogen gas and water vapor as per this chemical equation:
<u>2. Mole ratio</u>
<u>3. Volume ratio</u>
Since, both species are gases and are at same temperature and pressure, the volume ratio is equal to the mol ratio.
Thus, the volume ratio is:
<u>4. Use the volume ratio with the known amount of water produced</u>
C. Distance from Earth
The observed brightness of a star (the apparent magnitude) to an absolute magnitude, you need to know the distance [d], to the star. Alternatively, if we know the distance and the apparent magnitude [m] of a star, we can calculate its absolute magnitude [d].
*paraphrased from "COSMOS.com"
If your equation is <span>Cu+NO^- 3-->Cu^2+NO, then the answer is
</span><span>2 Cu + 1 NO3{-} → 1 Cu^{2+} + 3 NO
</span>
To check if it is balance, this is the solution:
2- Cu- 2
3- N -3
3- O -3
The answer is:
the molarity = 50 moles/liters
The explanation:
when the molarity is = the number of moles / volume per liters.
and when the number of moles =2.5 moles
and the volume per liters = 0.05 L
so by substitution:
the molarity = 2.5moles/0.05L
= 50 moles /L
