Answer:
ΔH rxn = -1010 kJ/molC₂H₂
Explanation:
To obtain the enthalpy change for a reaction from bond energies what we do is to make an inventory of the bonds broken and formed for the balanced chemical reaction:
C₂H₂ + 5/2O₂ ⇒ 2CO₂ + H₂O
Bond Broken Bonds Formed
2 C-H + 1 C≡C + 5/2 O=O 4C=O + 2 H-O
Enthalpy bonds broken:
2 mol (456 kJ/mol)+ 1 mol (962 kJ/mol) + 5/2 mol (499 kJ/mol) = 3121.5 kJ
Enthalpy bond formed:
4 mol (802 kJ/mol) + 2 mol (462 kJ/mol) = 4132.0 kJ
ΔH rxn = H broken - H formed = 3121.5 kJ - 4132.0 kJ = - 1010 kJ (per mol C₂H₂ )
I think the correct answers are X2Y and X3Y, X2Y5 and X3Y5, and X4Y2 and X3Y,
for the following reason:
If you look at the combining masses of X and Y in
each of the two compounds,
The first compound contains 0.25g of X combined with
0.75g of Y
so the ratio (by mass) of X to Y = 1 : 3
The second compound contains 0.33 g of X combined with
0.67 g of Y
so the ratio (by mass) of X to Y = 1 : 2
Now, you suppose to prepare each of these two
compounds, starting with the same fixed mass of element Y ( I will choose 12g
of Y for an easy calculation!)
The first compound will then contain 4g of X and 12g
of Y
The second compound will then contain 6g of X and
12g of Y
<span>The ratio which combined
the masses of X and the fixed mass (12g) of Y
= 4 : 6
<span>or 2 : 3 </span>
So, the ratio of MOLES of X which combined with the
fixed amount of Y in the two compounds is also = 2 : 3 </span>
The two compounds given with the plausible formula must therefore contain
the same ratio.
Answer:- 544.5 mL of water need to be added.
Solution:- It is a dilution problem. The equation used for solving this type of problems is:
where, 
is initial molarity and 
is the molarity after dilution. Similarly, 
is the volume before dilution and 
is the volume after dilution.
Let's plug in the values in the equation:
Volume of water added = 907.5mL - 363mL = 544.5 mL
So, 544.5 mL of water are need to be added to the original solution for dilution.
<span>Answer is </span>(3)
- Sodium Nitrate.<span>
</span>Normally ionic bonds can be seen between
metals and non-metals while covalent
bonds present between
non-metals. Another thing that determines the bond nature is electronegativity
value of the atoms.
If the electronegativity difference
is high, then that bond tends to be an ionic bond.<span>
</span><span>Sodium nitrate consists of </span>Na⁺<span> and </span>NO₃⁻ ions. Hence, the bond
between Na⁺ and NO₃⁻<span> is an </span>ionic
bond. <span><span>
NO</span>₃⁻ </span><span>is made from </span>N <span>and </span>O<span>. Both are </span>non-metallic
atoms. <span>The </span>electronegativities <span>of </span>N <span>and </span>O <span>are </span>3.0 <span>and </span>3.5 <span>respectively. Hence, there is </span>no
big difference between
electronegativity values (3.5 - 3.0 = 0.5<span>). Hence, the bond
between N and O is a </span><span>covalent
bond. </span>
Answer: When you strike a tennis ball with a racket, the slight springyness of the racket allows the ball to propel forward
Explanation:
