08. A sample of a gas at 100°C, occupies 275 mL at 1.52atm. What volume will it occupy at 2.75 atm and 200°C?

302ml

Explanation:

using PV=NRT for the first given piece of information, we need to find N, 1.52x275=Nx8.31x100

will give an N value of 0.5

now we substitute this into the second given piece of information to find V:

2.75xV=0.5x8.31x200

will give a V value of 302ml

since they used the SI units, the pressure given in atm must be converted into pa by multiplying it with 101.3x10^3

1.52atm will be 153976pa

2.75atm will be 278575pa

also the temperature was given in °C but the SI unit is in K

so to convert, we just add 273

100°C will be 373K

and 200°C will be 473K

use the same technique to find N first, substitute it into the second piece of information to get V

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

if you need further assistance, let me know: )

~ trueboss72