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Yuliya22 [10]
3 years ago
13

During lab, you learned about exothermic and endothermic heats of solution. which compounds below could be used for a hot pack?

(select all that apply.)
Chemistry
1 answer:
tatiyna3 years ago
8 0
What are the options? It says select all that apply...
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7 0
3 years ago
A very old tree limb contains an amount of carbon-14 that is approximately 1/8 of the current atmospheric 14C levels.. Calculate
Tomtit [17]

A.       The radioactive decay equation is N = N0e^{-ln(2)*t/T }

where T is the half-life (5730 years), N0 is the number of atoms at time t = 0 and N is the number at time t.

Rewriting this as:

(N/N0) = e^{-ln(2)*t/T }

Since N = (1/8) N0 and substituting known values:

1/8 = e^{-ln(2)*t/5730}

Taking ln of both sides:

ln(1/8)= -ln(2)*t/5730

t = - 5730 * ln(1/8) / ln (2)

t = 17,190 years

The tree was cut down 17,190 years ago.

B.   N0 = 1,500,000 carbon-14 atoms

Since N = (1/8) N0

N = 187,500 carbon atoms left

3 0
2 years ago
In case of accidental contact with chemicals, how long should the eyes be flushed at the eyewash station
FromTheMoon [43]

Answer:

See the answer below

Explanation:

<em>The duration of flushing the eyes at the eyewash station in case of accidental contact with chemicals depends of the nature of the chemical.</em>

If the chemical is known to be a <u>non-irritant or mild-irritant</u> one, a <u>5-minute </u>washing time is recommended as the first aid. before seeking the help of a physician,

For <u>moderate to severe irritant</u> chemicals, an immediate <u>15-20 minutes</u> washing period is recommended before seeking further medical help.

For <u>corrosive and strong alkalis</u> chemicals, <u>30 and 60 minutes</u> washing are recommended respectively before seeking the attention of a physician.

However, if the nature of the chemical is unknown,<u> a minimum of 20-minutes washing is generally recommended</u> as first aid before seeking immediate medical help.

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2 years ago
What is the Bohr model for potassium?
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This is Bohrs model for potassium

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Raw eggs are scrambled with a fork
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