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Andrei [34K]
3 years ago
5

Please help in Chemistry!!!! 15 points! I added a picture below...

Chemistry
2 answers:
aleksandr82 [10.1K]3 years ago
7 0
Yeah, the answer would be choice B because it drops from 40 to 20 so it's -20
krek1111 [17]3 years ago
5 0
The answer would be choice B because the energy decreased by 20 J
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crimeas [40]
No, actually adawadawada and awawawaw usually addawadadaw but also awawawa so it’s a possibility but very rare.
3 0
3 years ago
A chemist dissolves of pure potassium hydroxide in enough water to make up of solution. Calculate the pH of the solution. (The t
Leya [2.2K]

Answer:

12.99

Explanation:

<em>A chemist dissolves 716. mg of pure potassium hydroxide in enough water to make up 130. mL of solution. Calculate the pH of the solution. (The temperature of the solution is 25 °C.) Be sure your answer has the correct number of significant digits.</em>

Step 1: Given data

  • Mass of KOH: 716. mg (0.716 g)
  • Volume of the solution: 130. mL (0.130 L)

Step 2: Calculate the moles corresponding to 0.716 g of KOH

The molar mass of KOH is 56.11 g/mol.

0.716 g × 1 mol/56.11 g = 0.0128 mol

Step 3: Calculate the molar concentration of KOH

[KOH] = 0.0128 mol/0.130 L = 0.0985 M

Step 4: Write the ionization reaction of KOH

KOH(aq) ⇒ K⁺(aq) + OH⁻(aq)

The molar ratio of KOH to OH⁻is 1:1. Then, [OH⁻] = 0.0985 M

Step 5: Calculate the pOH

We will use the following expression.

pOH = -log [OH⁻] = -log 0.0985 = 1.01

Step 6: Calculate the pH

We will use the following expression.

pH + pOH = 14

pH = 14 - pOH = 14 -1.01 = 12.99

8 0
3 years ago
Hello there
Mumz [18]
The answer is the third one because density is mass divided by volume so 80 divided by 10 is 8
6 0
2 years ago
Read 2 more answers
Explain how the following experimental errors affect the final calculation of the kilocalories per gram for a food item. Be spec
Ainat [17]

Answer:

a) the final kilocalories per gram for food will be less because the mass was reduced

b)the final kilocalories per gram for food will be less since

c) the final kilocalories per gram for food will be less since the reaction will eventually go to completion

d) the final kilocalories per gram for food will be more.

Explanation:

a) the final kilocalories per gram for food will be less because the mass was reduced from 110.3 to 101.3g

b)the final kilocalories per gram for food will be less since some marshmallow fell off before the reaction

c) the final kilocalories per gram for food will be less since the reaction will eventually go to completion

d) the final kilocalories per gram for food will be more since the thermometer that got stuck will add to the value of final kilocalories per gram

6 0
4 years ago
What are the top three sources of the U.S electricity generation?
SVETLANKA909090 [29]

Answer: The three major categories of energy for electricity generation are fossil fuels (coal, natural gas, and petroleum), nuclear energy, and renewable energy sources

Explanation:

7 0
3 years ago
Read 2 more answers
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