<span>12.7 g Li*(1 mole Li/6.94 g Li)=1.83 moles of Li
34.7 g N2(1 mole N2/28 g N2)=1.23
1.83 moles Li*(2 moles Li3N/6 mole Li)(34.82 grams Li3N/1 mole Li3N)=21.24g Li3N </span>
Standard equation: N2(g)+3H2(g)==>2NH3(g), so through stoichiometry, (13.5 mol H2)(2 mol NH3/3 mol H2), yielding 9 moles of NH3<span />
Answer:
B
Explanation:
If the temperature of the water goes up, the reaction is exothermic (heat is being given away by the equation -- more precisely the reactants of the equation). Only A and B can be true. In order for the reaction to occur, the water has to absorb the heat. It's temperature goes up. Remember that minus sign. It is almost the key fact for this question.
The question is not as hard as it looks, but that is easy for me to say.
m = 100 g
c = 4.2 J/(g * oC)
deltaT = 21 - 20 degrees = 1 degree.
Heat = 100 * 4.2 * 1
Heat = 420 J
Heat = 420 * [1 kJ/1000 J]
Heat = -0.42 kJ
B
Answer : The new pressure of the gas will be, 468.66 atm
Explanation :
Boyle's Law : This law states that pressure of the gas is inversely proportional to the volume of the gas at constant temperature and number of moles.
(At constant temperature and number of moles)
or,
where,
= initial pressure of the gas = 74 atm
= final pressure of the gas = ?
= initial volume of the gas = 190 ml
= final volume of the gas = 30 ml
Now we put all the given values in the above formula, we get the final or new pressure of the gas.
Therefore, the new pressure of the gas will be, 468.66 atm
x21 +ANSWER
(i) Ne-22
(ii)1s2s22p6
(iii)21.3
An element X exists in three forms A, B and C in the ratio 1:2:3. If C has 10 protons and the number of neutrons in A, B and C are 10, 11 and 12 respectively,Give the following:(i) Representation of form C of the element X(ii) Electronic configuration of form B of the element(iii) Calculate the average atomic mass.
(i)C has 10 protons and 12 neutrons so a mass of 10 +12 =22
element 10 is Neon (Ne) so this isotope is Ne-22
(ii) they all have the sane atomic number so the same number of electrons
with an electronic structure of 1s2s22p6
(iii) A weighs 20, B weighs 21, C weighs 22
the ratio is 1:2:3
weighted average weight is therefor
(1X20 +2X21 +3X22)/6 =21.3
