If traveling at equal velocities, which object would have the most momentum?

Exactly how much time must elapse before 16 grams of potassium-42decays, leaving 2 grams of the original isotope?(1) 8 × 12.4 ho

AleksandrR [38]

The answer is (3) 3 × 12.4 hours

To calculate this, we will use two equations:
$(1/2) ^{n} =x$
$t_{1/2} = \frac{t}{n}$
where:
n - number of half-lives
x - remained amount of the sample, in decimals
 $t_{1/2}$ - half-life length
t - total time elapsed.

First, we have to calculate x and n. x is remained amount of the sample, so if at the beginning were 16 grams of potassium-42, and now it remained 2 grams, then x is:
2 grams : x % = 16 grams : 100 %
x = 2 grams × 100 percent ÷ 16 grams
x = 12.5% = 0.125

Thus:
 $(1/2) ^{n} =x$
 $(0.5) ^{n} =0.125$
$n*log(0.5)=log(0.125)$
$n= \frac{log(0.5)}{log(0.125)}$
$n=3$

It is known that the half-life of potassium-42 is 12.36 ≈ 12.4 hours.
Thus:
 $t_{1/2} = 12.4$
 $t_{1/2} *n = t$
 $t= 12.4*3$

Therefore, it must elapse 3 × 12.4 hours before 16 grams of potassium-42 decays, leaving 2 grams of the original isotope

7 0

3 years ago

Read 2 more answers

A group of students working in a high school chemistry lab believe they have discovered a new element! How exciting? Upon furthe

spayn [35]

Answer:

Explanation:

Information given about the element:

Number of protons = 74

Number of neutrons = 110

For the atomic number:

Neutral atoms such as this one would have their atomic number to be the same with their number of electrons and protons:

atomic number = number of protons = number of electrons

The atomic number would therefore be 74

For the mass number:

The mass of an atom is centrally concentrated within the tiny nucleus. The mass number is the sum of protons and neutrons in an atom. Protons and neutrons are nuclear particles and are called nucleons:

Mass number = number of protons + number of neutrons = 74+110=184

Is this a new element?

From the peroidic table, tungsten(W) perfectly fits this description of the atom. It has an atomic number of 74 and a mass number of approximately 184. The element is not a new element.

Is it solid, liquid, or gas?

The element is a hard metallic solid. It is a classified as a transition metal on the periodic table. Transition metals have very unique metals and are mostly solids.

4 0

3 years ago

Read 2 more answers

In order to reduce dependence on imported oil, the government of Jalica has imposed minimum fuel-efficiency requirements on all

liubo4ka [24]

Answer:

(B) The Jalican government did not intend the new fuel-eﬁiciency requirement to be a pollution-reduction measure.

Explanation:

What it was expressed is about to reduce dependence on imported oil.

6 0

3 years ago

If y = 15 when x = 60, find y when x = 45.

Delvig [45]

Y=15 x=60
•1/3 •1/3
y=5 x=45

4 0

2 years ago

Which of the following ions would represent the ion of an element from Group 1A?

svetoff [14.1K]

The best and the most correct answer among the choices provided by the question is the third choice. The ion that would represent the element from Group 1A is Z+. I hope my answer has come to your help. God bless and have a nice day ahead!

5 0

3 years ago