Answer:
9.94 mL, the volume of ethanol needed
Explanation:
The reaction is:
C₂H₅OH(l) + 3 O₂(g) → 2 CO₂(g) + 3 H₂O(l)
We convert the mass of the formed product to moles:
15 g . 1mol / 44g = 0.341 moles
2 moles of dioxide are produced by 1 mol of ethanol, in order to stoichiometry.
Therefore, 0.341 moles of CO₂ must be produced by (0.341. 1) / 2 = 0.1705 moles of alcohol.
We convert the moles to mass, and then, the mass to volume by the use of density.
0.1705 mol . 46 g / 1 mol = 7.84 g of ethanol
Ethanol density = Ethanol mass /Ethanol volume
Ethanol volume = Ethanol mass /Ethanol density → 7.84 g /0.789 g/mL =
9.94 mL
The quick deployment of the bag which I think is quite similar to a cushion and a balloon. It holds your head/face away from any hard surfaces. Although it does not protect your legs or other extremities that are out of the bags range.
Answer:
yes
Explanation:
because I think it is correct fo u
The full question asks to decide whether the gas was a specific gas. That part is missing in your question. You need to decide whether the gas in the flask is pure helium.
To decide it you can find the molar mass of the gas in the flask, using the ideal gas equation pV = nRT, and then compare with the molar mass of the He.
From pV = nRT you can find n, after that using the mass of gass in the flask you use MM = mass/moles.
1) From pV = nRT, n = pV / RT
Data:
V = 118 ml = 0.118 liter
R = 0.082 atm*liter/mol*K
p = 768 torr * 1 atm / 760 torr = 1.0105 atm
T = 35 + 273.15 = 308.15 K
n = 1.015 atm * 0.118 liter / [ 0.082 atm*liter/K*mol * 308.15K] =0.00472 mol
mass of gas = mass of the fask with the gas - mass of the flasl evacuated = 97.171 g - 97.129 g = 0.042
=> MM = mass/n = 0.042 / 0.00472 = 8.90 g/mol
Now from a periodic table or a table you get that the molar mass of He is 4g/mol
So the numbers say that this gas is not pure helium , because its molar mass is more than double of the molar mass of helium gas.
Almost all properties are common to elements within a single group on the periodic table. They react with water in the same way, they have the same number of valence electrons thereby having the same valency, the number of shells in the atom of the element increases by one as we move down the group.
In general, they have the same chemical properties as chemical properties depend on the number of electrons in the valence shell i.e. the outermost shell in the atom of an element.
