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dezoksy [38]
3 years ago
14

A substance undergoes a change. Which of the following indicates that the change was a chemical change?

Chemistry
1 answer:
hoa [83]3 years ago
4 0
The answer is A. <span>The substance changed shape.

There you go!</span>
You might be interested in
What is the percent ionization of a 1.8 M HC2H3O2 solution (Ka = 1.8 10-5 ) at 25°C?
xz_007 [3.2K]

Answer:

B) 0.32 %

Explanation:

Given that:

K_{a}=1.8\times 10^{-5}

Concentration = 1.8 M

Considering the ICE table for the dissociation of acid as:-

\begin{matrix}&CH_3COOH&\rightleftharpoons &CH_3COOH&+&H^+\\ At\ time, t = 0 &1.8&&0&&0\\At\ time, t=t_{eq}&-x&&+x&&+x\\ ----------------&-----&-&-----&-&-----\\Concentration\ at\ equilibrium:-&1.8-x&&x&&x\end{matrix}

The expression for dissociation constant of acid is:

K_{a}=\frac {\left [ H^{+} \right ]\left [ {CH_3COO}^- \right ]}{[CH_3COOH]}

1.8\times 10^{-5}=\frac{x^2}{1.8-x}

1.8\left(1.8-x\right)=100000x^2

Solving for x, we get:

<u>x = 0.00568  M</u>

Percentage ionization = \frac{0.00568}{1.8}\times 100=0.32 \%

<u>Option B is correct.</u>

8 0
3 years ago
Consider the chemical equations shown here.
Alona [7]

Answer:

-304.1

Explanation:

Just took it on Edge 2020

5 0
3 years ago
Read 2 more answers
Who or what has had the biggest influence on your thoughts about chemistry?
vampirchik [111]

Answer:

My chemistry teacher from my sophomore year.

Explanation:

I took class online last year and he was an older teacher and really didn't know how to use a computer. I asked for help multiple times and he would tell me to look the answer up. I would watch countless videos and still wouldn't understand. He ended up failing me that year and I had summer school. To this day, I dislike chemistry because of him.

3 0
3 years ago
A block of metal has a mass of 51.11 g and displaces 71.46 ml of water. Calculate the density of the metal in g/ml.
Damm [24]

Answer:

The answer is

<h2>0.07 g/mL</h2>

Explanation:

The density of a substance can be found by using the formula

density =  \frac{mass}{volume}  \\

From the question

mass of metal = 5.11 g

volume = 71.46 mL

The density of the metal is

density =  \frac{5.11}{71.46}  \\  = 0.071508536...

We have the final answer as

<h3>0.07 g/mL</h3>

Hope this helps you

8 0
3 years ago
Under what circumstances might be important to know the activity tendencies of elements?
ad-work [718]

Answer: It is very important to know the activity tendencies of the elements. The activity tendencies tells us about whether the element is reactive or not.

In the redox-reaction where there is a need to know the oxidizing agent and reducing agent, we can know it easily from the activity tendencies. The elements lying above the reactivity series are better reducing agents.

In the substitution reactions, the activity tendencies helps us to know which element will replace the other. The element lying above in the series will replace the element lying below it.

MX+NY \rightarrow MY+NX

where, N is an element that lies above in the reactivity series

M is an element that lies below in the reactivity series

3 0
3 years ago
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