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.
The answer is c) to repair and replace other cells.
Cell division is the replication of cells by dividing itself into two, it does not prevent replication. Cell division does not make glucose either and cell division does not make ATP.
Answer: umm, yes? DUH
Explanation: touch some falling out of a tap
Answer:
BaSO₄
Explanation:
It is possible to know if a bond is ionic or covalent using the electronegativity of the atoms in the bond. If electronegativity difference is higher than 1.8, the bond is ionic, if doesn't, bond is covalent.
CaI₂ has the Ca-I bond where electronegativity of Ca and I are 1 and 2.66. Difference of electronegativity is 1.66 → <em>Bond is covalent.</em>
COS has the C-O and C-S bonds where electronegativity of C, O and S are 2.55, 3.44 and 2.55. Difference of electronegativity are 0.89 and 0 → <em>Bonds are covalent.</em>
BaSO₄ has the Ba-O and O-S bonds where electronegativity of Ba, O and S are 0.89, 3.44 and 2.55. Difference of electronegativity are 2.55 and 0.89 → <em>Bonds are ionic and covalent respectively</em><em>.</em>
SF₆ has the S-F bond where electronegativity of S and F are 2.55 and 3.98. Difference of electronegativity is 1.43 → <em>Bond is covalent.</em>