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3 years ago

What is the percent of carbon-14 remaining after two half-lives?

Chemistry

1 answer:

Maslowich3 years ago

7 0

After one half-life, one half is remaining. After two half-lives one fourth is remaining. So that would be 25%

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The bulb lights up in the circuit. Only two rods are conductors of electricity. Which one of the rods, X, Y or Z is definitely a

meriva

Answer: Rod X.

Explanation:

Ok, the electricity starts in the top left part. First, it must travel in the X rod, then it keeps traveling until it reaches the parallel path, and it can go to the Z rod, to the Y rod, or to both of them, and then it reaches the bulb (the circle with a X inside of it).

We know that two rods are conductors of electricity.

Now, suppose the case where rods Z and Y are the ones that conduct electricity, this means that X does not conduct electricity, then when the current reaches to X it stops (because X does not conduct) then the electricity never reaches the rods Z and Y, and then the electricity never reaches the bulb, but we know that the bulb lights up, so we must have that X is one of the conducting rods.

Then, if for example, Y does not conduct electricity, the electricity still can run through the Z rod and eventually reach the bulb.

So we can conclude that the rod that is definitely a conductor of electricity is rod X

4 0

3 years ago

72.0 grams of water how many miles of sodium with react with it?

Flura [38]

Answer:

$\large \boxed{\text{8.00 mol}}$

Explanation:

We will need a balanced chemical equation with masses, moles, and molar masses.

1. Gather all the information in one place:

Mᵣ: 18.02

2Na + H₂O ⟶ 2NaOH + H₂

m/g: 72.0

2. Moles of H₂O

$\text{Moles of H$_{2}$O} = \text{72.0 g H$_{2}$O} \times \dfrac{\text{1 mol H$_{2}$O}}{\text{18.02 g H$_{2}$O}} = \text{3.996 mol H$_{2}$O}$

3. Moles of Na

The molar ratio is 2 mol Na/1 mol H₂O.

$\text{Moles of Na} = \text{3.996 mol H$_{2}$O} \times \dfrac{\text{2 mol Na}}{\text{1 mol H$_{2}$O}} = \textbf{8.00 mol Na}\\\\\text{The water will react with $\large \boxed{\textbf{ 8.00 mol}}$ of Na}$

7 0

3 years ago

Platinum is one of the most dense elements (d = 21.5 g/cm3). What is the volume of a 10.0 g sample of the metal?

kvasek [131]

Answer:

0.465

Explanation:

To find the volume of a substance, divide the mass by the density.

M/D = V

10.0 / 21.5 = 0.4651163

Then round to 3 significant figures: and the density is 0.465

4 0

3 years ago

How many sulfur atoms would be present in 41.8 moles of sulfur?

Montano1993 [528]

Answer:

2.51 x 10*25 atoms

6 0

4 years ago

Use the following chemical equation to answer the question:

garik1379 [7]

2 atome nitrogen , 1 is correct

5 0

3 years ago