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3 years ago

What are five kinds of evidence you can use to determine if a chemical reaction has occurred?

Chemistry

1 answer:

telo118 [61]3 years ago

5 0

Change of odor, change of color, change of temperature, change of energy, or loss of heat

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At a certain temperature this reaction follows first-order kinetics with a rate constant of 0.086 s^-1:

tankabanditka [31]

It takes 31 s for 1.27 M H₃PO₄ to decrease its concentration to 7.0% of its initial value following first-order kinetics.

<h3>What is first-order kinetics?</h3>

First-order kinetics occur when a constant proportion of a reactant disappears per unit time.

Let's consider the following first-order kinetics reaction with a rate constant k = 0.086 s⁻¹.

2 H₃PO₄(aq) = P₂O₅(aq) + 3 H₂O(aq)

Given the initial concentation is [H₃PO₄]₀ = 1.27 M, the concentration representing 7.0% of this value is:

[H₃PO₄] = 7.0% × 1.27 M = 0.089 M

We can calculate the time elapsed (t) using the following expression.

ln ([H₃PO₄]/[H₃PO₄]₀) = - k × t

ln (0.089 M/1.27 M) = - 0.086 s⁻¹ × t

t = 31 s

It takes 31 s for 1.27 M H₃PO₄ to decrease its concentration to 7.0% of its initial value following first-order kinetics.

Learn more about first-order kinetics here: brainly.com/question/18916637

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8 0

2 years ago

Will the following reaction occur?

uranmaximum [27]

Answer: Yes, magnesium will replace hydrogen because magnesium is higher on the activity series list.

Explanation:

A single replacement reaction is one in which a more reactive element displaces a less reactive element from its salt solution.

A general single displacement reaction can be represented as :

$X+YZ\rightarrow XZ+Y$

$Mg+2HCl\rightarrow MgCl_2+H_2$

When magnesium is added to hydrochloric acid, magnesium being more reactive than hydrogen displaces hydrogen atom its salt solution and lead to formation of magnesium chloride and hydrogen gas.

3 0

3 years ago

What is sodium + oxygen when doing ionic bonds

Marta_Voda [28]

When burning sodium (Na) in oxygen (O2), you get sodium oxide (Na2O) and/or sodium peroxide (Na2O2). At high pressures, you can additionally get sodium superoxide (NaO2).

4 Na + O2 → 2 Na2O, and then partially 2 Na2O + O2 → 2 Na2O2.

Under normal conditions, approximately 20% of the mixture is Na2O2.

6 Na + 2 O2 → 2 Na2O + Na2O2

hope it helps

5 0

3 years ago

Don't know how to solve

faltersainse [42]

Happy Valentines Day! <3

8 0

3 years ago

Which particle diagram represents a mixture of three substances

Anni [7]

Following the key in the diagram (see the attached image), the only particle diagram that represents a mixture of three substances is diagram 2.

To simplify it, let us replace the key in the diagram as follows;

atom of one element = A
atom of different element = B

Diagram 1 consists of only AA and AB

Diagram 2 consists of AA, BB, and AB.

Diagram 3 consists of AA and ABA

Diagram 4 consists of AA and BAB

Thus, only diagram 2 has a mixture of 3 substances.

More on mixtures can be found here: brainly.com/question/6594631

4 0

3 years ago