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vampirchik [111]

1 year ago

6

How many half-lives have passed in a sample that originally contained 5000 parent isotopes but now has only 625?

1 answer:

lilavasa [31]1 year ago

3 0

Answer:

3 half lives

Explanation:

5000 * (1/2)^n = 625 where n = number of half lives

log ( 625/5000) / log(1/2) = n = 3

5000 2500 1250 625

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If a certain species is found to have DNA composed of 17% cytosine, what would be the percentages of the other three bases?

Sergio [31]

Answer:

Adenine=33%

Thymine=33%

Guanine=17%

Explanation:

the base pairs percentages must be the same

7 0

2 years ago

Would anyone help <br> !!!!!

balu736 [363]

Answer

Explanation:

Protons would be the first answer since protons have a + charge. Neutrons would be second sicne neutrons have a neutral or 0 charge. Electrons would be the last since electrons have a - charge.

4 0

4 years ago

Read 2 more answers

9. Calculate the approximate number of atoms in a bacterium. Assume the average mass of an atom in the bacterium is 10 times the

Natali5045456 [20]

The question is incomplete, the complete question is :

Calculate the approximate number of atoms in a bacterium. Assume the average mass of an atom in the bacterium is 10 times the mass of a hydrogen atom.(Hint the mass of hydrogen atom is on order of $10^{-27}$ kg and the mass of bacterium is on order of $10^{-15}$ kg

Answer:

The total numbers of atom in bacterium are $10^{12}$ .

Explanation:

Mass of hydrogen atom, m= $10^{-27}$ kg

Mass of bacterium , M= $10^{-15}$ kg

Mass of bacterium atom =m'

Given ; $m' =10\times m$

$m'=10\times 10^{-27} kg=10^{-26} kg$

let the number of atoms in bacterium be N

$m'\times N=M$

$N=\frac{M}{m'}=\frac{10^{-15} kg}{10^{-27} kg}=10^{12}$

The total numbers of atom in bacterium are $10^{12}$ .

5 0

3 years ago

How can the conductivity of a salt solution be decreased?

Musya8 [376]

Answer:

B. Add more water to decrease the concentration.

Explanation:

If we add more water to the solution, the concentration is decreased and like wise the conductivity of the solution.

Concentration is the amount of solute in a solution.
Conductivity deals with the ability of a solution to allow the passage of current.

Concentration and conductivity are directly proportional to one another. The higher the concentration, the higher the conductivity and vice versa.

Adding more water increases the amount of solvent and the concentration reduces.

4 0

3 years ago

7. What volume of a 0.10 mol/l HCl solution is needed to neutralize 10 ml of a 0.15

svp [43]

Answer: The volume of a 0.10 mol/l HCl solution needed to neutralize 10 ml of a 0.15 mol/l LiOH solution is 15 ml

Explanation:

To calculate the volume of acid, we use the equation given by neutralization reaction:

$n_1M_1V_1=n_2M_2V_2$

where,

$n_1,M_1\text{ and }V_1$ are the n-factor, molarity and volume of acid which is $HCl$

$n_2,M_2\text{ and }V_2$ are the n-factor, molarity and volume of base which is LiOH.

We are given:

$n_1=1\\M_1=0.10mol/L\\V_1=?mL\\n_2=1\\M_2=0.15mol/L\\V_2=10mL$

Putting values in above equation, we get:

$1\times 0.10\times V_1=1\times 0.15\times 10\\\\V_1=15mL$

Thus the volume of a 0.10 mol/l HCl solution needed to neutralize 10 ml of a 0.15 mol/l LiOH solution is 15 ml

5 0

4 years ago