How many moles of O2 are needed to react completely with 3 mol of H2S?

Carbon-14 has a half-life of 5720 years and this is a first order reaction. If a piece of wood has converted 75% of the carbon-1

liraira [26]

Answer: 1145.8 years

Explanation:

Half-life of carbon-14 = 5720 years

First we have to calculate the rate constant, we use the formula :

$k=\frac{0.693}{5720\text{years}}$

$k=1.21\times 10^{-4}\text{years}^{-1}$

Now we have to calculate the age of the sample:

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

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

where,

k = rate constant = $1.21\times 10^{-4}\text{years}^{-1}$

t = age of sample = ?

a = let initial amount of the reactant = 100 g

x = amount decayed = 75 g

a - x = amount left after decay process = 100 - 75 = 25g

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

$t==\frac{2.303}{1.21\times 10^{-4}}\log\frac{100}{25}$

$t=1145.8years$

8 0

3 years ago

Read 2 more answers

How are mass and volumes alike?

AlladinOne [14]

Kind of this is probably wrong Mass weight of solid, volume weight of liquid?

3 0

3 years ago

a solution is prepared by dissolving 55g of CaCl2 into 300g of water. if the Kf of water is -1.86 c/m, shat is the freezing poin

Zepler [3.9K]

Answer:

Relation between , molality and temperature is as follows.

T =

It is also known as depression between freezing point where, i is the Van't Hoff factor.

Let us assume that there is 100% dissociation. Hence, the value of i for these given species will be as follows.

i for = 3

i for glucose = 1

i for NaCl = 2

Depression in freezing point will have a negative sign. Therefore, d

depression in freezing point for the given species is as follows.

=

Therefore, we can conclude that given species are arranged according to their freezing point depression with the least depression first as follows.

Glucose < NaCl <

Explanation:

3 0

3 years ago

a student determined that it requires 106220 j of energy to vaporize 47g of water. is the student is right

shusha [124]

<h2>Answer:</h2>

He is right that the energy of vaporization of 47 g of water s 106222 j.

<h3>Explanation:</h3>

Enthalpy of vaporization or heat of vaporization is the amount of energy which is used to transform one mole of liquid into gas.

In case of water it is 40.65 KJ/mol. And 18 g of water is equal to one mole.

It means for vaporizing 18 g, 40.65 kJ energy is needed.

So for energy 47 g of water = 47/18 * 40.65 = 106.1 KJ

Hence the student is right about the energy of vaporization of 47 g of water.

7 0

3 years ago

Please indicate which of the compounds will yield postive results for the permanganate, ninhydrin, and ceric ammonium nitrate te

maks197457 [2]

The compounds will yield Positive results for the permanganate, ninhydrin, and ceric ammonium nitrate tests are

permanganate test= ethene,

ninhydrin=aspasyic acid Phenylalanine

ceric ammonium nitrate test= methanol

<h3>What is a compound?</h3>

Generally, A compound is simply defined as a substance made up of two or more different chemical elements held together by chemical bonds that are difficult to break.

In conclusion, For the permanganate test= ethene,

ninhydrin=aspasyic acid Phenylalanine

ceric ammonium nitrate test= methanol