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3 years ago

Which of these is an indication that a chemical reaction has occurred?

2 answers:

4 0

The following indication that a chemical reaction has occurred would be B. A change in colour in a substance. The other 3 are physical changes.

Taya2010 [7]3 years ago

3 0

The correct answer is B. A change of color in a substance

I took the test as well and that was the right one.

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Butene is an alkene explain how you know

ohaa [14]

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3 years ago

Which of the following contains the most atoms?

garik1379 [7]

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3 years ago

Why does raising the temperature cause a liquid to boil?

AlekseyPX

When the temperature increases the molecules of the liquid gain energy and kinetic energy increases, so it makes a pressure above the liquid

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3 years ago

Read 2 more answers

Which of the following values would you expect for the ratio of half-lives for a reaction with starting concentrations of 0.05M

harkovskaia [24]

Answer:

The expected ratio of half-lives for a reaction will be 5:1.

Explanation:

Integrated rate law for zero order kinetics is given as:

$k=\frac{1}{t}([A_o]-[A])$

$[A_o]$ = initial concentration

[A]=concentration at time t

k = rate constant

if, $[A]=\frac{1}{2}[A_o]$

$t=t_{\frac{1}{2}}$ , the equation (1) becomes:

$t_{\frac{1}{2}}=\frac{[A_o]}{2k}$

Half life when concentration was 0.05 M= $t_{\frac{1}{2}}$

Half life when concentration was 0.01 M= $t_{\frac{1}{2}}'$

Ratio of half-lives will be:

$\frac{t_{\frac{1}{2}}}{t_{\frac{1}{2}}'}=\frac{\frac{[0.05 M]}{2k}}{\frac{[0.01 M]}{2k}}=\frac{5}{1}$

The expected ratio of half-lives for a reaction will be 5:1.

6 0

3 years ago

Calculate the number of molecules present in 11 moles of H2O.

DedPeter [7]

Answer:

$11 \times 6.022 \times {10}^{23} \\ = 66.242\times {10}^{23} \: of \: \\ water \: molecules$

6 0

3 years ago