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dezoksy [38]
3 years ago
15

Which one is a chemical reaction? Why?

Chemistry
1 answer:
Alex17521 [72]3 years ago
3 0

Answer:

Copper turns green on exposure to air

Explanation:

Liquid water freezes to form ice: Physical change

Reason: Water can melt back when it becomes ice.

Copper turns green on exposure to air: Chemical change

Reason: The copper can not change back from the green state when it turns green.

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The formation of iodine is described by the following chemical equation:
olga nikolaevna [1]

Answer:

N2O2(g) +O2(g) ===> 2NO2(g)

Explanation:

For a nonelementary reaction, the reaction equation is described as the sum of all the steps involved. All these steps constitute the reaction mechanism. Each step in the mechanism is an elementary reaction. The rate law of the overall reaction involves the rate determining step (slowest step) in the reaction sequence.

Now look at the overall reaction 2NO(g) + O2(g) ---------> 2NO2(g)

The two steps in the mechanism are

2NO(g) --------->N2O2(g) (fast)

N2O2(g) +O2(g) -------> 2NO2(g) (slow)

Summing all the steps and cancelling out the intermediate N2O2(g), we obtain the reaction equation;

2NO(g) + O2(g) ---------> 2NO2(g)

Hence the answer.

7 0
3 years ago
How is the life cycle of a star similar to that of a human?
QveST [7]
Stars have a life cycle, just like people: they are born, grow, change over time, and eventually grow old and die. Most stars change in size, color, and class at least once in their lifetime.
Brainliest?
4 0
2 years ago
Read 2 more answers
what is the formula used to find the heat energy for vaporization heat energy for fusion hrat energy for liquid
Alinara [238K]

Answer:

Use the formula q = m·ΔHv in which q = heat energy, m = mass, and ΔHv = heat of vaporization.

Explanation:

:)

8 0
3 years ago
What is the concentration if 20 grams of NaOH was dissolved in enough water to make a 250 mL NaOH solution?
gizmo_the_mogwai [7]

Answer: 1 molar NaOH contains 40 grams of NaOH per every liter of water

Explanation:

so 2 M NaOH contains twice that amount, ie. 80 grams per liter. Then, ine 250 ml of weater, there should be 80/4 = 20 grams of solid NaOH dissolved.

3 0
3 years ago
You have 345 mL of a 2.5 M NaCl solution. If you boil the water until the volume of the solution is 250 mLwhat will the molarity
HACTEHA [7]

The molarity of the solution will be 3.45 M

<h3>Further explanation </h3>

Dilution is the process of adding a solvent to get a more dilute solution.

The moles(n) before and after dilution are the same.

Can be formulated :

M₁V₁=M₂V₂  

M₁ = Molarity of the solution before dilution  

V₁ = volume of the solution before dilution  

M₂ = Molarity of the solution after dilution  

V₂ = Molarity volume of the solution after dilution

The initial solution

345 mL of a 2.5 M NaCl solution.

M₁=2.5 M

V₁=345 ml

The solution after boiled :

V₂=250 ml

\tt M_2=\dfrac{M_1.V_1}{V_2}\\\\M_2=\dfrac{2.5\times 345}{250}\\\\M_2=3.45~M

5 0
3 years ago
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