Answer:
1- Option (A)
2- Option (A)
Explanation:
The pressure is often defined as the force per unit area. In the atmosphere, the pressure is maximum at the troposphere and is tightly packed near the ground surface. The troposphere is the region where the temperature decreases with the increasing height. The atmospheric pressure at sea level is nearly 1013.2 millibar (mb). The difference in the pressure in this layer causes the wind that is responsible for the occurrence of different types of weather patterns.
The earth and the sun maintains the shortest distance at its Perihelion position, which takes place in the month of January during the winter season in the northern hemisphere. And on the other hand, the earth is far away from the sun at its Aphelion position that takes place in the month of July.
Hence, the correct answers are given above.
Answer:
Explanation:
Mg²⁺ is divalent , hence
Molecular weight / 2 = equivalent weight .
.25 moles = 2 x .25 equivalents = .5 equivalents .
Cl⁻ is monovalent so
molecular weight = equivalent weight
.50 mole = .50 equivalent
Total equivalent = .50 of Mg²⁺ + .50 of Cl⁻
= 1 equivalent .
A. Increases as you move from left to right across a period
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.
You must remember that oxidation number of hydrogen in acids is always +1, oxidation number of oxygen in oxides & acids is always -2... metals has always oxidation number on plus!
group NO3 comes from HNO3...and oxidation number of whole acid group is always on minus and equal to the amount of hydrogen atoms in this acid... so oxidation number of NO3 = -1
we have 2 NO3 groups so 2*(-1) = -2 and that is the reason why oxidation number of Fe in this formula must be +2... because sum of all elements always gives 0!
Now we could count of oxidation number for nitrogen... we write HNO3 and start counting from right to left:
3*(-2) from oxygens + 1 from hydrogen = -5
so nitrogen must have +5 oxidation number... because sum all in formula must be 0.
