Answer:
v = 534.5mL
m = 597.15g
Density = 9.23g/mL
Density = 9.125g/mL
Explanation:
Density = mass/ volume
For the first question
Density = 1.59g/mL
Mass = 834.01g
Volume = ?
Using the above formula we have 1.59 = 834.01/v
v = 834.01/1.59
v = 534.5mL
For the second question
Density =0.9167g/mL
Volume = 651.41mL
Mass =?
Using the above formula we have
0.9167 =m/651.41
Cross multiply
m = 0.9167 x 651.41
m = 597.15g
For the third question
Mass =803.44g
Volume=87.03mL
Density =?
Density = 803.44/87.03
= 9.23g/mL
For the fourth
Density = 56.85/6.23
= 9.125g/mL
Let's eliminate these one by one.
The first pair would not be the same, as X would most likely be in group IA, and Y would be in group VIIA, because of their tendency to gain and lose electrons.
The second pair would also violate the same rule, but X would most likely be in group IIA, and Y would most likely be in group VIA.
The third pair would not be the same, as X is most likely in group VIIA, and since Y has eight valence electrons, it is most likely a noble gas.
The final pair has X with atomic number 15, making it phosphorous. Phosphorous wants to gain 3 electrons to have a full octet of 8 outer "valence" electrons, and Y would also like to gain 3 electrons. This means it is possible that the final pair would be in the same group.
Answer:
6.67 moles
Explanation:
Given that:-
Moles of hydrogen gas produced = 10.0 moles
According the reaction shown below:-
3 moles of hydrogen gas are produced when 2 moles of aluminium undergoes reaction.
Also,
1 mole of hydrogen gas are produced when 
moles of aluminium undergoes reaction.
So,
10.0 moles of hydrogen gas are produced when 
moles of aluminium undergoes reaction.
<u>Moles of Al needed = moles = 6.67 moles</u>
They are in the same period (horizontal)
Answer:
A) positive; added
Explanation:
Based on the reaction:
2NaHCO3(s) + 129kJ → Na2CO3(s) + H2(g) + CO2(g)
<em>2 moles of NaHCO3 requires 129kJ to produce 1 mole of Na2CO3, 1 mole of H2 and 1 mole of CO2.</em>
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That means, the energy must be added being, thus, an exothermic reaction. The exothermic reactions have ΔH >0.
Thus, right answer is:
A) positive; added
