Answer:
B. calcium has electrons in more energy levels than magnesium
Explanation:
atoms are made of three types of subatomic particles - electrons, protons and neutrons.
Neutrons and protons reside in the nucleus of the atom and electrons reside in energy shells
electronic configuration for both Ca and Mg are as follows
Mg - 2,8,2
Ca - 2,8,8,2
outermost energy shell of Mg with electrons is the third energy level
whereas outermost energy shell of Ca with electrons is the fourth energy shell
therefore Ca has a larger atomic radius than Mg as it has one more energy shell than Mg in which electrons reside
I think it might be A. i am not totally sure though
The given balanced reaction is,
The stoichiometric coefficients of each element or compound represents the number of moles of that element or compound required for the complete reaction to take place.
The mole ratios of different products and reactants will be:
So the mole ratio comparing iron (Fe) and oxygen gas (
) is
4 : 3
Answer:
The correct answer is 0.047 mol/L
Explanation:
The atmospheric air is a mixture of gases. We can assume an ideal behavior of the gas and use the ideal gas equation:
PV= nRT
where P is the pressure, V is the volume, n is the number of moles, R is a constant (0.082 L.atm/K.mol) and T is the temperature in K.
We have to first convert the pressure from Torr to atm:
760 Torr= 1 atm
⇒ 718 Torr x 1 atm/760 Torr = 0.945 atm
Then, we convert the temperature from ºC to K:
0ºC = 273 K
⇒ -29ºC+273= 244 K
Finally, we introduce the data in the equation and calculate de densitiy, which is the moles per liters of gas (n/V):
PV = nRT
n/V= P/RT
n/V = (0.945 atm)/(0.082 L.atm/K.mol x 244 K) = 0.047 mol/L
