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3 years ago

Which of the following is true about the concept of half-life?

Chemistry

2 answers:

Reptile [31]3 years ago

8 0

Its A. because it measures the rate of the decay of the isotope

Margaret [11]3 years ago

3 0

it is A Half-life measures the rate of decay of a radioisotope.

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Given that 25.0 mL of mercury has a mass of 340.0 g, calculate (a) the density of mercury and (b) the mass of 120.0 mL of mercur

natita [175]

Answer :

(a) The density of mercury is, 13.6 g/ml

(b) The mass of 120.0 ml of mercury is, 1632 grams

Explanation :

(a) Now we have to calculate the density of mercury.

Given :

Volume of mercury = 25.0 ml

Mass of mercury = 340.0 g

Formula used :

$\text{Density of mercury}=\frac{\text{Mass of mercury}}{\text{Volume of mercury}}$

$\text{Density of mercury}=\frac{340.0g}{25.0ml}=13.6g/ml$

Therefore, the density of mercury is, 13.6 g/ml

(b) Now we have to calculate the mass of 120.0 ml of mercury.

As, 25.0 ml of mercury has mass = 340.0 g

So, 120.0 ml of mercury has mass = $\frac{120.0ml}{25.0ml}\times 340.0g=1632g$

Therefore, the mass of 120.0 ml of mercury is, 1632 grams

3 0

3 years ago

If 4.50 l of water vapor at 50.2 °c and 0.121 atm reacts with excess iron, how many grams of iron(iii) oxide will be produced?

Flura [38]

When the balanced equation for this reaction is:
2Fe + 3H2O → Fe2O3 + 3H2

and according to the vapour pressure formula:
PV= nRT
when we have P is the vapor pressure of H2O= 0.121 atm
and V is the volume of H2O = 4.5 L
and T in Kelvin = 52.5 +273 = 325.5 K
R= 0.08205 atm-L/g mol-K
So we can get n H2O
So, by substitution:
n H2O = PV/RT
= (0.121*4.5)/(0.08205 * 325.5) = 0.02038 gmol
n Fe2O3 = 0.02038 * (1Fe2O3/ 3H2O) = 0.00679 gmol
Note: we get (1FeO3/3H2O) ratio from the balanced equation.
we can get the Mass of Fe2O3 from this formula:
Mass = number of moles * molecular weight
when we have a molecular weight of Fe2O3 = 159.7
= 0.00679 * 159.7 = 1.084 g
∴ 1.084 gm of Fe2O3 will produced

6 0

3 years ago

Read 2 more answers

A fixed amount of oxygen gas is held in a .500 L tank at a pressure of 4.39 atm. The tank is connected to an empty 1.50 L tank b

DochEvi [55]

Answer:

1.0975 atm.

Explanation:

According to Boyle’s Law: " At constant temperature , the volume of a given quantity of a gas varies inversely with its pressure".

P α 1/V.

∴ P₁V₁ = P₂V₂.

P₁ = 4.39 atm, V₁ = 0.5 L.

P₂ = ??? atm, V₂ = 2.0 L.

∴ P₂ = P₁V₁/V₂ = (4.39 atm)(0.5 L) / (2.0 L) = 1.0975 atm.

5 0

2 years ago

For the following reaction, the equilibrium constant Kc is 0.80 at a certain temperature. If the concentration of NO(g) and NOBr

velikii [3]

Answer:

[Br₂] = 1.25M

Explanation:

2NO (g) + Br₂ (g) ⇄ 2NOBr (g)

Eq 0.80M ? 0.80M

That's the situation told, in the statement.

Let's make the expression for Kc

Kc = [NOBr]² / [Br₂] . [NO]²

Kc = 0.80² / [Br₂] . [0.80]²

0.80 = 1 / [Br₂]

[Br₂] = 1 / 0.80 → 1.25

4 0

3 years ago

If f is a reactive nonmetal, which other element or elements shown here do you expect to also be a reactive nonmetal?

vichka [17]

You did not include the list but F is fluorine. The first halogen.

So, you can expect that the other members of the same group (halogens, column 17 of the periodic table) exhibit similar chemical behavior (reactivity).

So, I am sure your list contains one or more of theses elements: Cl (chlorine), Br (bromine), and I (iodine).

All of them you can expect to also be reactive non metal.

3 0

3 years ago