All categories

4 years ago

7. Carbon-11 has a half-life of 20 minutes. Explain what this means.

Chemistry

1 answer:

Nikolay [14]4 years ago

6 0

Answer:

half life of carbon 11=20 mins

it means that after 20 mins the given sample of carbon-11 will reduce by half of its original value

Explanation:

You might be interested in

How many atp molecules can be produced when a six carbon fatty acid is completely oxidized through the fatty acid spiral?

Karolina [17]

The simplified formula for the determination of the number of ATP molecules produced from fat oxidation is:
5(n-1) + 12n - 2

This formula is derived using the amount of energy produced using each turn of the Kerb's cycle, which has two-carbon units fed to it via beta oxidation (also referred to as the fatty acid spiral).
In order to use this formula, we require the value of n. n is the number of two-carbon units that the fatty acid molecule will produce. This means:

n = 6 / 2 = 3
Using n = 3

5(3 - 1) + 12(3) - 2

44 ATP molecules

7 0

4 years ago

Suppose you have a crystal composed of elements X and Y in which the radius ratio is approximately ½, so that the sodium chlorid

WINSTONCH [101]

Answer:

XY would have a higher melting point than NaCl.

Explanation:

The electrostatic force (F) between ions in an ionic lattice can be estimated using Coulomb's Law.

$F=k.\frac{q_{1}.q_{2}}{r^{2} }$

where,

k is the Coulomb's constant

q₁ and q₂ are the charges of the ions

r is the distance between the ions

X⁺⁺ and Y⁻⁻ are doubly charged with respect to Na⁺ and Cl⁻ so the force between them is 4 times the force between Na⁺ and Cl⁻. Since the force is stronger, it would require more energy to break it to take it to the liquid state, so a higher melting point is expected.

7 0

3 years ago

If you mix 50mL of 0.1 M TRIS acid with 60 mL of0.2 M<br> TRIS base, what will be the resulting pH?

Katyanochek1 [597]

<u>Answer:</u> The pH of resulting solution is 8.7

<u>Explanation:</u>

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in mL)}}$

<u>For TRIS acid:</u>

Molarity of TRIS acid solution = 0.1 M

Volume of solution = 50 mL

Putting values in above equation, we get:

$0.1M=\frac{\text{Moles of TRIS acid}\times 1000}{50mL}\\\\\text{Moles of TRIS acid}=0.005mol$

<u>For TRIS base:</u>

Molarity of TRIS base solution = 0.2 M

Volume of solution = 60 mL

Putting values in above equation, we get:

$0.2M=\frac{\text{Moles of TRIS base}\times 1000}{60mL}\\\\\text{Moles of TRIS base}=0.012mol$

Volume of solution = 50 + 60 = 110 mL = 0.11 L (Conversion factor: 1 L = 1000 mL)

To calculate the pH of acidic buffer, we use the equation given by Henderson Hasselbalch:

$pH=pK_a+\log(\frac{[salt]}{[acid]})$

$pH=pK_a+\log(\frac{[\text{TRIS base}]}{[\text{TRIS acid}]})$

We are given:

$pK_a$ = negative logarithm of acid dissociation constant of TRIS acid = 8.3

$[\text{TRIS acid}]=\frac{0.005}{0.11}$

$[\text{TRIS base}]=\frac{0.012}{0.11}$

pH = ?

Putting values in above equation, we get:

$pH=8.3+\log(\frac{0.012/0.11}{0.005/0.11})\\\\pH=8.7$

Hence, the pH of resulting solution is 8.7

6 0

4 years ago

The dipole measured for HI is 0.380 D. The bond distance is 161 pm. What is the percent ionic character of the HI bond?

Feliz [49]

Answer:

Percent ionic character of HI bond is 4.91%.

Explanation:

<h3>Given Data:</h3>

Measured Dipole = 0.380D

bond distance = d = 161pm = 1.61*10^-8 cm

<h3>Calculation:</h3>

% ionic character is determined by following equation:

% ionic= (dipole measured/dipole calculated)*100

Now,

$Dipole(calc)=qd$

$Dipole(calc)= (1.6*10^{-19}*3*10^{9})esu *1.61*10^{-8}cm$

(In above step 3*10^8 is multiplied to convert coulomb into esu)

$Dipole(calc)=7.728*10^{-18} esu*cm$

As,

$10^{-18}esu*cm= 1D$

So,

$Dipole(calc)=7.728D$

Now we can % ionic character using above equation:

%ionic=(0.380D/7.728D)*100

% ionic character=4.91%

5 0

4 years ago

Substances that make up a mixture __________ their own properties once they are combined to form a mixture. Please help. I need

Stels [109]

I believe the answer to this is;
Substances that make up a mixture RETAIN their own properties once they are combined to form a mixture.
I believe the answer is RETAIN because the combination in question is a MIXTURE. A mixture is a combination of various substances. In the case of mixtures, all the substances retain their own properties. That is; they remain the way they are and do not change. An example of a mixture is air. And to prove that air is a mixture;
The components of air retain their individual properties.
The components of air cannot be represented by a chemical formula
When the components of air combine, they do not show any form of chemical change, like heat release, change in pressure.....
Hope i helped, have a nice day.

8 0

3 years ago