Answer:
3.052 × 10^24 particles
Explanation:
To get the number of particles (nA) in a substance, we multiply the number of moles of the substance by Avogadro's number (6.02 × 10^23)
The mass of Li2O given in this question is as follows: 151grams.
To convert this mass value to moles, we use;
moles = mass/molar mass
Molar mass of Li2O = 6.9(2) + 16
= 13.8 + 16
= 29.8g/mol
Mole = 151/29.8g
mole = 5.07moles
number of particles (nA) of Li2O = 5.07 × 6.02 × 10^23
= 30.52 × 10^23
= 3.052 × 10^24 particles.
Answer:
the original answer is 38.9km (3sf)
Answer:
50
Explanation:
We will need a balanced equation with masses, moles, and molar masses of the compounds involved.
1. Gather all the information in one place with molar masses above the formulas and masses below them.
Mᵣ: 30.01 32.00 46.01
2NO + O₂ ⟶ 2NO₂
Mass/g: 80.00 16.00
2. Calculate the moles of each reactant
![\text{moles of NO} = \text{80.00 g NO} \times \dfrac{\text{1 mol NO}}{\text{30.01 g NO}} = \text{2.666 mol NO}\\\\\text{moles of O}_{2} = \text{16.00 g O}_{2} \times \dfrac{\text{1 mol O}_{2}}{\text{32.00 g O}_{2}} = \text{0.5000 mol O}_{2}](https://tex.z-dn.net/?f=%5Ctext%7Bmoles%20of%20NO%7D%20%3D%20%5Ctext%7B80.00%20g%20NO%7D%20%5Ctimes%20%5Cdfrac%7B%5Ctext%7B1%20mol%20NO%7D%7D%7B%5Ctext%7B30.01%20g%20NO%7D%7D%20%3D%20%5Ctext%7B2.666%20mol%20NO%7D%5C%5C%5C%5C%5Ctext%7Bmoles%20of%20O%7D_%7B2%7D%20%3D%20%5Ctext%7B16.00%20g%20O%7D_%7B2%7D%20%5Ctimes%20%5Cdfrac%7B%5Ctext%7B1%20mol%20O%7D_%7B2%7D%7D%7B%5Ctext%7B32.00%20g%20O%7D_%7B2%7D%7D%20%3D%20%5Ctext%7B0.5000%20mol%20O%7D_%7B2%7D)
3. Calculate the moles of NO₂ we can obtain from each reactant
From NO:
The molar ratio is 2 mol NO₂:2 mol NO
![\text{Moles of NO}_{2} = \text{2.333 mol NO} \times \dfrac{\text{2 mol NO}_{2}}{\text{2 mol NO}} = \text{2.333 mol NO}_{2}](https://tex.z-dn.net/?f=%5Ctext%7BMoles%20of%20NO%7D_%7B2%7D%20%3D%20%5Ctext%7B2.333%20mol%20NO%7D%20%5Ctimes%20%5Cdfrac%7B%5Ctext%7B2%20mol%20NO%7D_%7B2%7D%7D%7B%5Ctext%7B2%20mol%20NO%7D%7D%20%3D%20%5Ctext%7B2.333%20mol%20NO%7D_%7B2%7D)
From O₂:
The molar ratio is 2 mol NO₂:1 mol O₂
![\text{Moles of NO}_{2} = \text{0.5000 mol O}_{2}\times \dfrac{\text{2 mol NO}_{2}}{\text{1 mol Cl}_{2}} = \text{1.000 mol NO}_{2}](https://tex.z-dn.net/?f=%5Ctext%7BMoles%20of%20NO%7D_%7B2%7D%20%3D%20%20%5Ctext%7B0.5000%20mol%20O%7D_%7B2%7D%5Ctimes%20%5Cdfrac%7B%5Ctext%7B2%20mol%20NO%7D_%7B2%7D%7D%7B%5Ctext%7B1%20mol%20Cl%7D_%7B2%7D%7D%20%3D%20%5Ctext%7B1.000%20mol%20NO%7D_%7B2%7D)
4. Identify the limiting and excess reactants
The limiting reactant is O₂ because it gives the smaller amount of NO₂.
The excess reactant is NO.
5. Mass of excess reactant
(a) Moles of NO reacted
The molar ratio is 2 mol NO:1 mol O₂
![\text{Moles reacted} = \text{0.500 mol O}_{2} \times \dfrac{\text{2 mol NO}}{\text{1 mol O}_{2}} = \text{1.000 mol NO}](https://tex.z-dn.net/?f=%5Ctext%7BMoles%20reacted%7D%20%3D%20%5Ctext%7B0.500%20mol%20O%7D_%7B2%7D%20%5Ctimes%20%5Cdfrac%7B%5Ctext%7B2%20mol%20NO%7D%7D%7B%5Ctext%7B1%20mol%20O%7D_%7B2%7D%7D%20%3D%20%5Ctext%7B1.000%20mol%20NO%7D)
(b) Mass of NO reacted
![\text{Mass reacted} = \text{1.000 mol NO} \times \dfrac{\text{30.01 g NO}}{\text{1 mol NO}} = \text{30.01 g NO}](https://tex.z-dn.net/?f=%5Ctext%7BMass%20reacted%7D%20%3D%20%5Ctext%7B1.000%20mol%20NO%7D%20%5Ctimes%20%5Cdfrac%7B%5Ctext%7B30.01%20g%20NO%7D%7D%7B%5Ctext%7B1%20mol%20NO%7D%7D%20%3D%20%5Ctext%7B30.01%20g%20NO%7D)
(c) Mass of NO remaining
Mass remaining = original mass – mass reacted = (80.00 - 30.01) g = 50 g NO
Answer:
There are 10.0 moles of beryllium oxide in a 250 grams sample of the compound.
Explanation:
We can calculate the number of moles (η) of BeO as follows:
![\eta = \frac{m}{M}](https://tex.z-dn.net/?f=%20%5Ceta%20%3D%20%5Cfrac%7Bm%7D%7BM%7D%20)
Where:
m: is the mass = 250 g
M: is the molar mass = 25.0116 g/mol
Hence, the number of moles is:
![\eta = \frac{250 g}{25.0116 g/mol} = 10.0 moles](https://tex.z-dn.net/?f=%20%5Ceta%20%3D%20%5Cfrac%7B250%20g%7D%7B25.0116%20g%2Fmol%7D%20%3D%2010.0%20moles%20)
Therefore, there are 10.0 moles of beryllium oxide in a 250 grams sample of the compound.
I hope it helps you!
The correct answer for this question is this one: "<span>In transpiration, because some of its properties change, water undergoes a physical change but keeps its identity. In photosynthesis, because its identity changes, water undergoes a chemical change</span>. "
Hope this helps answer your question and have a nice day ahead.