<u>Answer:</u>
<em>False</em>
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<u>Explanation:</u>
The energy required to break a bond is endothermic that is energy is absorbed to break a bond.
The energy is released in the formation of a bond that is energy is released when a bond is formed.
The formula to find the ∆H of the reaction is
∆H (reaction) = ∆H (bonds Broken) - ∆H (bonds formed)
For example
contains one N ≡ N triple bond (Bond breaking 946 KJ per mol)
contains a single H-H bond (bond breaking 436KJ per mol)
contains 3 N-H single bonds (389 KJ per mol)
So,
∆H (bonds broken) = 946 + (3 × 436) = 2254 KJ
∆H (Bonds formed ) = (2 × 3 × 389) = 2334 KJ
So,
∆H (reaction) = 2254 KJ - 2334 KJ = - 80 KJ
The reaction is Exothermic
In this example we see energy required to break the bond is lesser than energy released in forming the bond.
So we can conclude if the amount of energy required to break bonds in the reactants is more than the amount of energy released in forming bonds in the products, then the reaction will have a positive change in enthalpy and ∆H is positive (+∆H) .
Answer:
5.8 x 6.022x10^23 =3.49276x10^24
or
5.8 x 6.02x10^23 =3.4916x10^24
One mole of lithium (Li) is equal to 6.022 x 10^23 atoms of lithium.
Avogadro's constant
D) If only 6.6 grams of water are produced, what is the percent yield?
Write out the balanced equation:
2C2H6 + 7O2 --> 4CO2 + 6H2O
Then, determine the limiting reagents:
16.8 grams of C2H6/30.06 g/mol of C2H6 = 0.46 mol
45.8 grams of O2/32 g/mol of O2 = 1.4 mol
0.46 mol of C2H6/2 = 0.23
1.4 mol of O2/7 = 0.20
<em>- Dioxygen is the limiting reagent. </em>
Find the theoretical molar yield of water:
There is a 7 mol of O2 to 6 mol of H2O ratio (according to the balanced equation).
<em>We can setup a proportion;</em>
7/6 = 0.23/x
0.196 = x
So, 0.196 mol of water will be produced.
How many grams of water will be produced in the reaction?
<em><u>0.196 mol of H2O x 18 g/mol of H2O = 3.53 grams of H2O </u></em>
Answer:
26.73 mg.
Explanation:
- Firstly, we can calculate the no. of moles of magnesium chlorate (Mg(ClO₃)₂):
no. of moles of magnesium chlorate (Mg(ClO₃)₂) = mass/molar mass = (72.03 mg)/(191.21 g/mol) = 0.377 mmol.
<em>Every 1.0 mole of magnesium chlorate (Mg(ClO₃)₂) contains 2.0 moles of Cl.</em>
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∴ The no. of moles of Cl in magnesium chlorate (Mg(ClO₃)₂) = 2(0.377 mmol) = 0.754 mmol.
∴ The mass of Cl are found in 72.03 mg of magnesium chlorate (Mg(ClO₃)₂) = (no. of moles of Cl)(atomic mass of Cl) = (0.754 mmol)(35.453 g/mol) = 26.73 mg.
The first and the last choice is the same, aren't they?
