HELP!!!

A sample of 28 Mg decays initially at a rate of 53500 disintegrations per minute, but the decay rate falls to 10980 disintegrati

prisoha [69]

Answer : The half life of 28-Mg in hours is, 6.94

Explanation :

First we have to calculate the rate constant.

Expression for rate law for first order kinetics is given by:

$k=\frac{2.303}{t}\log\frac{a}{a-x}$

where,

k = rate constant

t = time passed by the sample = 48.0 hr

a = initial amount of the reactant disintegrate = 53500

a - x = amount left after decay process disintegrate = 53500 - 10980 = 42520

Now put all the given values in above equation, we get

$k=\frac{2.303}{48.0}\log\frac{53500}{42520}$

$k=9.98\times 10^{-2}hr^{-1}$

Now we have to calculate the half-life.

$k=\frac{0.693}{t_{1/2}}$

$9.98\times 10^{-2}=\frac{0.693}{t_{1/2}}$

$t_{1/2}=6.94hr$

Therefore, the half life of 28-Mg in hours is, 6.94

8 0

3 years ago

Determine whether the bonds in CCl4 and N2 are polar or non-polar. If the bond is polar, assign the partial positive and negativ

stira [4]

Refer to the attachment

7 0

3 years ago

In the reaction N2 + 3H2 → 2NH3, what is the mole ratio of hydrogen to nitrogen?

uranmaximum [27]

Answer: The mole ratio of hydrogen to nitrogen is 3 mole: 1 mole, 3:1

Explanation:

•Mole ratios are determined using the coefficients of the substances in the balanced chemical equation. •Each coefficient represents the number of mole of each substance in the chemical reaction.

•The mole ratio can be determined by first writing out a balanced chemical equation for the reaction.

For this reaction the balanced chemical equation is

N2(g) + 3H2(g) ----> 2NH3(g)

1mol:3mol : 2mol

From the equation we can see that 1 mole of N2(g) reacts with 3 moles of H2(g) or 3 moles of H2(g) react with 1 mole of N2(g) to produce 2 moles of NH3(g).

Therefore, the mole ratio of hydrogen to nitrogen is 3 mole: 1 mole, 3:1

7 0

3 years ago

How do ionic bonds differ from covalent bonds?

Alja [10]

Ionic bonds are a metal and a non metal bond and a covalent bond is two no metals banded together.

4 0

2 years ago

A mixture of C3H8 and C2H2 has a mass of 2.8 g. It is burned in excess O2 to form a mixture of water and carbon dioxide that con

astraxan [27]

Answer:

The mass of C2H2 in the mixture is 0.56gram using the ratio of carbon in the products contributed by the C2H2.

Explanation:

The balanced equation for the reaction is: C3H8 + 2C2H2 + 10O2 >> 7CO2 + 6H2O.

From the reaction, we know that the oxygen was in excess, this will make the Carbon sources the limiting agents in the reaction. The details of the reaction showed that the ratio of water to the carbon dioxide is 1.6:1. This also means that the expected mole of carbon dioxide will be 7/1.6, which is 3.75moles.

The individual balanced equation of reaction is:

C3H3 +5O2 >> 3CO2 + 4H2O

and 2C2H2 + 5O2 >>4CO2 + 2H2O. From this one can quickly tell that the propane is in sufficient supply as it produces 3 moles of CO2 out of the expected 3.75 moles obtained above. Leaving 0.75moles of CO2 to the ethyne.

The mass of ethyne in the mixture will therefore be: 0.75/3.75 X 2.8 = 0.56g.

4 0

3 years ago