Answer:
The accurate answer is 596.5 kJ.
Explanation:
The question specifies that the mass of ethanol, C2H5OH, is 20 grams.
The molar mass of ethanol is 46 g/mol.
To find the moles of ethanol, we use the formula:
n = mass / molar mass
= 20/46 = 0.435 moles
According to the question, the standard heat of combustion for ethanol is 1372 kJ/mol. Hence, one mole releases 1372 kilojoules during combustion.
The energy produced from burning 20 grams of ethanol completely is 0.435 * 1372 = 596.5 kJ.
Answer: 0.0164 molar concentration of hydrochloric acid in the resulting solution.
Explanation:
1) Molarity of 0.250 L HCl solution: 0.0328 M
The amount of HCl in the 0.250 L solution = 0.0082 moles
2) Molarity of 0.100 L NaOH solution: 0.0245 M
The amount of NaOH in the 0.100 L solution = 0.00245 moles
3) Determining the concentration of hydrochloric acid in the final solution.
0.00245 moles of NaOH will neutralize 0.00245 moles of HCl from the original 0.0082 moles of HCl.
The total volume of the mixture becomes 0.100 L + 0.250 L = 0.350 L
Remaining moles of unreacted HCl = 0.0082 moles - 0.00245 moles = 0.00575 moles
Concentration of the remaining HCl:
0.0164 molar concentration of hydrochloric acid in the resulting solution.
Answer:
B, C
Explanation:
The Lewis dot structures that are valid are for B and C.
Regarding A;
The Lewis representation of carbon is correct. Each of the four dots symbolizes the four valence electrons.
However, the nitrogen with a single dot above, to the left, and below and a -3 charge isincorrect. For it to have a -3 charge, it must possess 8 Lewis dots (two on each side).
The nitrogen showing four dots (on top, right, bottom and left) is incorrect.
In B;
An oxygen having two dots positioned above and below with one dot on both sides is correct , as the 6 dots indicate oxygen's valence electrons.
In C;
A carbon shows two dots at each position and has a charge of +4. This is correct because the charge reflects that it has gained four electrons giving it 8 valence electrons.
In D;
An oxygen shows two dots above, to the left and below, with a charge of -2. This is incorrect as not all Lewis dots are present. Two are missing.
Boyle's law describes the relationship between gas pressure and volume.
It asserts that at a constant temperature, pressure is inversely proportional to gas volume.
PV = k
where P represents pressure, V denotes volume, and k is a constant.
P1V1 = P2V2
where the parameters for the initial condition are on the left, and the parameters for the second condition appear on the right side of the formula.
By substituting values into the equation: 4.00 atm x 500 L = 8.0 atm x V
V calculates to 250 L.
Thus, the new volume becomes 250 L.
The concentration of the HCl solution can be determined as follows:
The reaction equation is written as
NaOH + HCl = NaCl + H2O
Next, the moles of NaOH are calculated: moles = molarity x volume /1000
= 5 x 2/1000 = 0.01 moles
Using the mole ratio of NaOH to HCl, which is 1:1, the moles of HCl is also equal to 0.01 moles
The concentration is given by: concentration = moles/volume x 1000
= 0.01/10 x 1000 = 1M
