Answer:
B. rubbing your hands together to get warm,
Explanation:
Rubbing your hands together warms them by converting work into thermal energy.
Hope it helps ;)
Answer:
94.1 %
Explanation:
We firstly determine the equation:
2H₂O + O₂ → 2H₂O₂
2 moles of water react to 1 mol of oxygen in order to produce 2 moles of oxygen peroxide.
We convert the mass of oxygen to moles:50 g . 1mol /32g = 1.56 mol
Certainly oxygen is the limiting reactant.
2 moles of water react to 1 mol of oxygen.
13 moles of water may react to 13/2 = 6.5 moles. (And we only have 1.56)
As we determine the limiting reactant we continue to the products:
1 mol of O₂ can produce 2 moles of H₂O₂
Then 1.56 moles of O₂ will produce (1.56 . 2) = 3.125 moles
We convert the moles to mass: 3.125 mol . 34 g/mol= 106.25 g
That's the 100% yield or it can be called theoretical yield.
Percent yield = (Yield produced / Theoretical yield) . 100
(100g / 106.25 g) . 100 = 94.1 %
Answer:- 0.800 moles of the gas were collected.
Solution:- Volume, temperature and pressure is given for the gas and asks to calculate the moles of the gas.
It is an ideal gas law based problem. Ideal gas law equation is used to solve this. The equation is:
PV=nRT
Since it asks to calculate the moles that is n, so let's rearrange this for n:
![n=\frac{PV}{RT}](https://tex.z-dn.net/?f=n%3D%5Cfrac%7BPV%7D%7BRT%7D)
V = 19.4 L
T = 17 + 273 = 290 K
P = 746 mmHg
we need to convert the pressure from mmHg to atm and for this we divide by 760 since, 1 atm = 760 mmHg
![P=746mmHg(\frac{1atm}{760mmHg})](https://tex.z-dn.net/?f=P%3D746mmHg%28%5Cfrac%7B1atm%7D%7B760mmHg%7D%29)
P = 0.982 atm
R = ![0.0821\frac{atm.L}{mol.K}](https://tex.z-dn.net/?f=0.0821%5Cfrac%7Batm.L%7D%7Bmol.K%7D)
Let's plug in the values in the equation to get the moles.
![n=\frac{0.982atm*19.4L}{0.0821\frac{atm.L}{mol.K}*290K}](https://tex.z-dn.net/?f=n%3D%5Cfrac%7B0.982atm%2A19.4L%7D%7B0.0821%5Cfrac%7Batm.L%7D%7Bmol.K%7D%2A290K%7D)
n = 0.800 moles
So, 0.800 moles of the gas were collected.
Beryllium fluoride I believe is the correct answer