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dsp73
3 years ago
13

calculate the change in enthalpy, if the reactants have an enthalpy of 315 kj and the products have an enthalpy of 375 kj

Chemistry
1 answer:
sineoko [7]3 years ago
5 0

25% is the answer, i believe.

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Hey! I was wondering how to get the solution to this question!
zzz [600]

Answer:

6.22 × 10⁻⁵

Explanation:

Step 1: Write the dissociation reaction

HC₆H₅COO ⇄ C₆H₅COO⁻ + H⁺

Step 2: Calculate the concentration of H⁺

The pH of the solution is 2.78.

pH = -log [H⁺]

[H⁺] = antilog -pH = antilog -2.78 = 1.66 × 10⁻³ M

Step 3: Calculate the molar concentration of the benzoic acid

We will use the following expression.

Ca = mass HC₆H₅COO/molar mass HC₆H₅COO × liters of solution

Ca = 0.541 g/(122.12 g/mol) × 0.100 L = 0.0443 M

Step 4: Calculate the acid dissociation constant (Ka) for benzoic acid

We will use the following expression.

Ka = [H⁺]²/Ca

Ka = (1.66 × 10⁻³)²/0.0443 = 6.22 × 10⁻⁵

3 0
3 years ago
How many moles of solute are in 250.0 mL of a 3.00 M HCl solution?
cestrela7 [59]
0.250 L*3M=0.250 L*3mol/L= 0.750 mol
8 0
3 years ago
What is the percent composition HCN?
kupik [55]

Answer:

see calculations in explanation

Explanation:

percent = part/total x 100%

part = ∑ atomic mass of element

  • hydrogen = 1.008 amu (atomic mass units)
  • carbon = 12.011 amu
  • nitrogen = 14.007 amu

total = ∑ molecular mass of compound

       = H amu  +  C amu +  Namu

       = 1.008 amu + 12.011 amu + 14.007 amu

       = 27.026 amu

%H = (1.008amu/27.026amu)100% = 3.730%

%C = (12.011amu/27.026amu)100% = 44.442%

%N = (14.007amu/27.026amu)100% = 51.827%

Check results ∑%values = 100%

3.730% + 44.442% + 51.827% = 99.999% ≅ 100%

7 0
3 years ago
Convert 500 inches to m. <br> 1000mm =1m<br> 1inch = 2.54 cm <br> 10mm=1cm
stira [4]

Answer:

12.7m

Explanation:

FORMULA  

for an approximate result, divide the length value by 39.370078

3 0
3 years ago
What observations and inferences can you make from this picture?
Salsk061 [2.6K]
I know they are fishing and there is an alligator in the lake. The alligator might grab the bait and attack the fishers.

Hope I helped!
Let me know if you need anything else!
~ Zoe
6 0
3 years ago
Read 2 more answers
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