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3 years ago

If 50% of a radioactive element remains after 4000 years, what is the half-life?

Chemistry

1 answer:

ANTONII [103]3 years ago

4 0

Hey there!

A half-life means after a certain amount of time, half of that substance will be gone/changed after that time.

If 50%, or half, of the element remains after 4000 years, that means the half life must be 4000 years.

Hope this helps!

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Penicillin is hydrolyzed and thereby rendered inactive by penicillinase, an enzyme present in some resistant bacteria. The mass

Arisa [49]

Answer:

The turnover number is the maximum substrate quantitiy converted to product per enzyme and per second. It can be calculate as follows:

$k_c = \frac{V_{max}}{[E]}$ with $[E]$ active enzyme concentration.

In this case we have Vmax an data to calculate $[E]$

$moles of E=\frac{10^{-9}g}{29600 g/mol}=3.38*10^{-14}$

$[E]=\frac{3.38*10^{-14}}{0.01 L}=3.38*10^{-12} M$

Now $k_c=\frac{6.8*10^-10}{3.38*10^{-12}}=201.28 min^{-1}$

it is not like any option.

If we assume that $V_{max}$ have the non usual units of $mol L^{-1} min^{-1}$ and it is $6.8*10^-10 mol min^{-1}$

So we need divide by the moles of E (in place of [E])

Now $k_c=\frac{6.8*10^-10}{3.38*10^{-14}}=20128 min^{-1} = 335 s{-1}$

(pass from $min^{-1}$ to $s^{-1}$ dividing by 60)

4 0

2 years ago

What do the coefficients in front of the reactants and products in a chemical reaction represent ?

makvit [3.9K]

It indicates the number of moles of reactants and products

Explanation:

The coefficients in front of the reactants and products in a chemical reaction represents the number of moles of reactants and products.

Every reaction is made up of equal number of moles of reactants and products. Thus, chemical equations are written in such a way to obey the law of conservation of matter.

The numbers used are usually whole numbers and the are very important in stoichiometry.

learn more:

Number of moles brainly.com/question/1841136

#learnwithBrainly

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2 years ago

What is Gallium Nitrite

olganol [36]

It is a binary direct bandgap semiconductor commonly used in light-emitting diodes since the 1990s

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cestrela7 [59]

I think the answer will be 60 and the reason why is because

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2 years ago

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Answer:

Low tides would be lower and high tides would be higher and any low lying coastline would be flooded

Explanation:

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If the moon got about 20 times closer it would make a gravitational force 400 times greater than what we are used to now

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