?

The decay of radioactive elements occurs at a fixed rate. The half-life of a radioisotope is the time required for one half of t

Stolb23 [73]

Answer:

100 grams of C-14 decays to 25 grams in 11,460 years.

The C-14 isotope is only useful for dating fossils up to about 50,000 years old

If an ancient bone contains 6.25% of its original carbon, then the bone must be 22,920 years old.

Explanation:

We already know that the half life of C-14 is 5,730 years. After the first half life, we have 50 grams remaining. This takes 5,730 years. After the second half life (11,460 years now gone) we have 25 grams of C-14 left.

If a fossil material is older than 50,000 years an undetectable amount of 14C is left in the sample hence Carbon-14 is no longer suitable for dating the sample.

From;

0.693/5730 = 2.303/t log (No/0.0625No)

Where;

t = time taken and No = initial amount of C-14

0.693/5730= 2.77/t

t = 22,920 years

6 0

3 years ago

what would the total pressure of a mixture of fluorine, chlorine, and bromine gases be if the partial pressure are 2.20 atm, 6.7

astraxan [27]

Answer:

The total pressure would be 8, 93 atm

Explanation:

We apply Dalton's laws, where for a gaseous mixture, the total pressure (Pt) is the sum of the partial pressures (Px) of the gases that make up the mixture.

Pt= Pxa + Pxb+ Pxc....

Pt=2, 20 atm+ 6, 70 atm+ 0,03 atm= 8, 93 atm

4 0

4 years ago

Consider the following chemical reaction: CO (g) + 2H2(g) ↔ CH3OH(g) At equilibrium in a particular experiment, the concentratio

AlexFokin [52]

Answer:

The equilibrium concentration of CH₃OH is 0.28 M

Explanation:

For the reaction: CO (g) + 2H₂(g) ↔ CH₃OH(g)

The equilibrium constant (Keq) is given for the following expresion:

Keq= $\frac{(CH3OH)}{(CO) x (H2)^{2}}$ =14.5

Where (CH3OH), (CO) and (H2) are the molar concentrations of each product or reactant.

We have:

(CH3OH)= ?

(CO)= 0.15 M

(H2)= 0.36 M

So, we only have to replace the concentrations in the equilibrium constant expression to obtain the missing concentration we need:

14.5= $\frac{(CH_{3}OH) }{(0.15 M) x (0.36 M) ^{2} }$

14.5 x (0.15 M) x $(0.36)^{2}$ = (CH₃OH)

0.2818 M = (CH₃OH)

6 0

3 years ago

True or false? In graphite, every atom forms strong bonds with four other atoms.

vagabundo [1.1K]

Answer: true

Explanation:

7 0

3 years ago

For the reaction H2(g) + I2(g) 2HI(g), Kc = 50.2 at 445ºC. If [H2] = [I2] = [HI] = 1.75  10-3 M at 445ºC, which one of these st

Soloha48 [4]

Answer: C) The concentration of HI will increase as the system approaches equilibrium.

Explanation:

Equilibrium constant is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios. It is expressed as $K_c$

K is the constant of a certain reaction when it is in equilibrium, while Q is the quotient of activities of products and reactants at any stage other than equilibrium of a reaction.

For the given chemical reaction:

$H_2(g)+I_2(g)\rightarrow 2HI(g)$