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Serhud [2]
3 years ago
10

The Half-Life of Pa-234 is 6.75 hours. How much (what fraction) of a sample of this isotope remains after 20.25 hours?

Chemistry
1 answer:
Grace [21]3 years ago
6 0
So in one hour half the amount remains (that's what half life means). In two hours 1/4 (or half of half) would remain and in three hours 1/8 would remain.
So the answer is 1/8
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For the reaction: 3 H2(g) + N2(g) <--> 2 NH3(g), the concentrations at equilbrium were [H2] = 0.10 M, [N2] = 0.10 M, and [
masya89 [10]

The equilibrium constant, k of the reaction in which case, the concentrations of the given reactants and products are as indicated is; Choice A; K = 3.1 x 10⁵

<h3>What is the equilibrium constant , k of the reaction as described in the task content?</h3>

It follows from above that the concentrations of the reactants and products are as follows; [H2] = 0.10 M, [N2] = 0.10 M, and [NH3] = 5.6 M at equilibrium.

Hence, the equilibrium constant of the reaction in discuss is;

K = [5.6]²/[0.10]³[0.10]

k = 5.6² × 10⁴

k = 3.136 × 10⁵

K = 3.1 × 10⁵.

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5 0
2 years ago
During which step in the Can Crush Lab did water vapor force air from the can?
irina [24]
When you heated the can with the bit of water inside and you boiled it over a flame, the water turned to vapor (gas) and the pressure in the inside of the can is different from the pressure on the outside of the can. When you placed the can into a ice water beaker or a container, the can shrunk it's size, decreasing it's mass and density. The can shrunk as a result of the inside pressure being equalized with the outside pressure.
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3 0
3 years ago
Using VSEPR theory which of the following would be the correct shape for nitrogen trifluoride?
RUDIKE [14]

Answer:

trigonal pyramidal

Explanation:

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Here, the nitrogen atom is the central atom and its outermost shell is surrounded by four electron pairs - one lone pair and three bond pairs. This means that it has a tetrahedral electron pair geometry.

However, due to the lone pair, the three fluorine atoms are arranged in a  trigonal pyramidal geometry. Hence the correct shape of the molecule is trigonal pyramidal.

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2 years ago
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dem82 [27]
Alkanes do not have a double bond, thus they are saturated. This makes them the simplest form of hydrocarbon, containing only hydrogen and carbon atoms. They are not very reactive as they don't have a double bond which can open up and join on to other molecules.
8 0
3 years ago
Read 2 more answers
If an unknown substance CANNOT be broken down into simpler substances, it is
lisov135 [29]

The correct answer is b. an element

The explanation:

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Ex: diamond will be broken into carbon as well.

and SUBSTANCE: Material composed of only one kind of matter throughout (same atoms or same molecules).

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3 years ago
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