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3 years ago

Select the correct answer.

2 answers:

4 0

D.) black text on a yellow background. There is much more contrast in the colors black and yellow than the other choices.

Igoryamba3 years ago

4 0

D black text on yellow background

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Someone help me please- Im stuck, will give brainliest

Vladimir79 [104]

Answer:

Option b.) Potassium ion, is written correctly.

Explanation:

Hope this helps! :)

7 0

3 years ago

Acetone is one of the most important solvents in organic chemistry. It is used to dissolve everything from fats and waxes to air

Yanka [14]

Answer: a. 79.6 s

b. 44.3 s

c. 191 s

Explanation:

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant

t = age of sample

a = let initial amount of the reactant

a - x = amount left after decay process

a) for completion of half life:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

$t_{\frac{1}{2}}=\frac{0.693}{k}$

$t_{\frac{1}{2}}=\frac{0.693}{8.7\times 10^{-3}s^{-1}}=79.6s$

b) for completion of 32% of reaction

$t=\frac{2.303}{k}\log\frac{100}{100-32}$

$t=\frac{2.303}{8.7\times 10^{-3}}\log\frac{100}{68}$

$t=44.3s$

c) for completion of 81 % of reaction

$t=\frac{2.303}{k}\log\frac{100}{100-81}$

$t=\frac{2.303}{8.7\times 10^{-3}}\log\frac{100}{19}$

$t=191s$

4 0

3 years ago

1. How much 6.0 M HNO3 is needed to neutralize 39 mL of 2.0 M KOH?

quester [9]

Answer:

For 2. the answer is 15.0 mL

For other examples, you can solve by exact way as I have solved the 2nd example.

I have writen down all the balanced chemical reaction equation for examples 1, 3, 4, 5 for you. ( picture 2 )

Explanation:

Please see the step-by-step solution in the picture attached below.(picture 1)

Hope this answer can help you. Have a nice day!

6 0

3 years ago

Công thức của A có dạng Ca(hco3)x có ptk là 162 tìm x

harina [27]

Answer:

Explanation:

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dodkekds

dldldle

5 0

2 years ago

Drag the tiles to the correct boxes to complete the pairs.

7nadin3 [17]

The correct answer is B.

Have a great day!

3 0

3 years ago

Read 2 more answers