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.
Answer:
64J of energy must have been released.
Explanation:
Step 1: Data given
One reactant contains 346 J of chemical energy, the other reactant contains 153 J of chemical energy.
The product contains 435 J of chemical energy.
Step 2:
Since the energy is conserved
Sum of energy of Reactants = Energy of Products
Sum of energy of Reactants = 346 J + 153 J = 499 J
The energy of the product = 435 J
435 < 499
This means energy must have been lost as heat.
Step 3: Calculate heat released
499 J - 435 J = 64 J
64J of energy must have been released.
When solid <span>iron (iii) hydroxide is dissolved into water, it ionizes or it dissociates into ions. These ions are the iron (iii) ions and the hydroxide ions. Iron(III) oxide is classified as a base when in aqueous solution since it produces hydroxide ions. It is a weak base so it does not completely dissociate into the solution. The dissociation equation would be:
Fe(OH)3 <-----> Fe3+ + OH-
To write a complete reaction, the reaction should be balanced wherein the number of atoms of each element in the reactant side and the product side should be equal. Also, the phases of the substances should be written. We do as follows:
</span>
Fe(OH)3 (s) <-----> Fe3+ (aq) + 3OH- (aq)
The melting and boiling point depend on the strength of the ihydrogen bonds. Hydrogen bonding will cause the higher the melting and boiling points because more energy is needed to break bonds between molecules.
Hydrogen bonds affect solubility in water, molecules with hydrogen bonds dissolve better in water.
