Answer:-3463 kJ and -3452kJ
Explanation:
ΔU is the change in internal energy of a system and its formula is;
ΔU = q + w
Where q represents heat transferred into or out of the system. Its value is positive when heat is transfer into the system and negative when heat is produced by the system.
W represents the work done on or by the system. Its value is positive when work is done on the system and negative when it is done by the system.
For the system in this question, we see that it produces heat which means heat is transferred out of the system, therefore the value of q is negative, it can also be seen that work is done by the system which means that w is also negative.
Therefore,
ΔU = -q-w
ΔU = -3452 kJ – 11kJ
= - 3463kJ
ΔH is the change in the enthalpy of a system and its formuls is;
ΔH = ΔU + Δ(PV)
By product rule Δ(PV) becomes ΔPV + PΔV
At constant pressure ΔP = 0. Therefore,
ΔH = -q-w + PΔV
w is equals to PΔV, So:
ΔH = -q
ΔH = -3452kJ
Explanation:
It is known that in a simple cubic unit cell the atoms are only present at the corner of the unit cell. This means that there are in total 8 atoms present in a simple cubic unit cell.
Therefore, in one simple cubic unit cell sharing of one atom is only 
.
Hence, the total number of atoms in a unit cell will be as follows.
= 1
Thus, we can conclude that there is 1 calcium atom present in each unit cell.
Answer:
Four covalent bonds.
Explanation:
Hello,
In this case, given the attached picture in which you can find the Lewis dot structure for metanal (formaldehyde) we can see two C-H bonds and two C-O bonds via a double bond, thus, we can compute the type of each bond given the electronegativities of hydrogen, carbon and oxygen which are 2.1, 2.5 and 3.5 respectively:
Thus, since both electronegativity difference are less 1.7 we infer that all of them are covalent, therefore, it has four covalent bonds, two C-H bonds and a double C-O bond.
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Answer:
16.9g of H₂O can be formed
Explanation:
Based on the chemical reaction, 2 moles of H₂ react per mole of O₂. To anser this question we must find limiting reactant converting the mass and volume of each reactant to moles:
<em>Moles H₂ -Molar mass: 2.016g/mol-:</em>
8.76g * (1mol / 2.016g) = 4.345 moles
<em>Moles O₂:</em>
PV = nRT
PV/RT = n
P = 1atm at STP
V = 10.5L
R = 0.082atmL/molK
T = 273.15K at STP
n = 1atm*10.5L / 0.082atmL/molK*273.15K
n = 0.469 moles of oxygen
For a complete reaction of 4.345 moles moles of hydrogen are required:
4.345 moles H2 * (1mol O2 / 2mol H2) = 2.173 moles of O2 are required. As there are just 0.469 moles, Oxygen is limiting reactant
Now, 1 mole of O2 produce 2 moles of H2O. 0.469 moles will produce:
0.469 moles O₂ * (2 moles H₂O / 1mol O₂) = 0.938 moles H₂O.
The mass is -Molar mas H₂O = 18.01g/mol-:
0.938 moles * (18.01g/mol) =
<h3>16.9g of H₂O can be formed</h3>
Answer:
A
Explanation:
Opposite charges attract therefore the electrons of one atom would be attracted by the nucleus (which contains protons). This heavily relies on a property called electronegativity. Which deals with the level of attraction a nucleus (the protons in the nucleus) have for electrons of other atoms.
