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FrozenT [24]
3 years ago
10

2 Which chemical reaction is exothermic and why A 25 degrees after 25 minutes B 23 degrees after 15 minutes C 30 degrees after 2

5 minutes D 22 degrees after 30 minutes
Chemistry
1 answer:
baherus [9]3 years ago
7 0

Answer:

C 30 degrees after 25 minutes

Explanation:

A reaction is exothermic if heat is evolved as the reaction proceeds. How do we know if heat was given out in the course of the reaction? We have to measure the temperature of the system using a thermometer as  the reaction progresses.

If the temperature becomes higher than room temperature (25 degrees), we can now conclude that the reaction is exothermic and heat was indeed given out during the course of the reaction.

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I have a chemistry question that I am needing help on please?​
aliina [53]
What country and grade are you?
Please tell me! I’m going to help you
8 0
3 years ago
Ca(OH)2 (s) precipitates when a 1.0 g sample of CaC2(s) is added to 1.0 L of distilled water at room temperature. If a 0.064 g s
borishaifa [10]

Answer:

Ca(OH)2 will not precipitate because Q<Ksp

Explanation:

Ksp for Ca(OH)2 has already been stated in the question as 8.0 x 10-8mol2dm-6

The value of the reaction quotient depends heavily on the concentration of the reactants. As the initial concentration of the calcium carbide decreases considerably, the reaction quotient decreases until Q<Ksp hence the Ca(OH)2 will not precipitate from solution.

The reaction equation is:

CaC₂(s) + H₂O ⇒ Ca(OH)₂ + C₂H₂

From

Ca(OH)2= Ca2+ + 2OH-

Concentration of solution= 0.064×1/64= 1×10-3

Since [Ca2+] = 1×10-3

[OH-]= (2×10-3)^2= 4×10^-6

Hence Q= 4×10^-9

This is less than the Ksp hence the answer.

4 0
3 years ago
The process of fermentation involves chemical reactions that convert solid glucose (C6H12O6) into aqueous ethanol and carbon dio
e-lub [12.9K]

Answer:

C6H12O6 —> 2C2H5OH + 2CO2

Explanation:

The equation for the reaction is given below:

C6H12O6 —> C2H5OH + CO2

We can balance the equation above as follow:

There are 12 atoms of H on the left side and 6 atoms of the right side. It can be balance by putting 2 in front of C2H5OH as shown below:

C6H12O6 —> 2C2H5OH + CO2

There are 6 atoms of C on the left side and 5 atoms on the right side. It can be balance by putting 2 in front of CO2 as shown below:

C6H12O6 —> 2C2H5OH + 2CO2

Now the equation is balanced.

4 0
3 years ago
A certain amount of hydrogen peroxide was dissolved in 100. mL of water and then titrated with 1.68 M KMnO4. What mass of H2O2 w
Stels [109]

Answer:

see explanation below

Explanation:

First to all, this is a redox reaction, and the reaction taking place is the following:

2KMnO4 + 3H2SO4 + 5H2O2 -----> 2MnSO4 + K2SO4 + 8H2O + 5O2

According to this reaction, we can see that the mole ratio between the peroxide and the permangante is 5:2. Therefore, if the titration required 21.3 mL to reach the equivalence point, then, the moles would be:

MhVh = MpVp

h would be the hydrogen peroxide, and p the permanganate.

But like it was stated before, the mole ratio is 5:2 so:

5MhVh = 2MpVp

Replacing moles:

5nh = 2MpVp

Now, we just have to replace the given data:

nh = 2MpVp/5

nh = 2 * 1.68 * 0.0213 / 5

nh = 0.0143 moles

Now to get the mass, we just need the molecular mass of the peroxide:

MM = 2*1 + 2*16 = 34 g/mol

Finally the mass:

m = 0.0143 * 34

m = 0.4862 g

8 0
3 years ago
Why is this image a good model for the Law of Conservation of Mass?
ZanzabumX [31]

Answer:

The Law of Conservation of Mass states that mass is neither created nor destroyed in chemical reactions. Since the number and type of atoms in the reactant side of the chemical equation are the same as on the product side, the Law of Conservation of Mass has been demonstrated.

Explanation:

In the answer.

8 0
3 years ago
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