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zlopas [31]
1 year ago
12

What is the half-life of a radioisotope if it decays to 25% of its original activity in 7 yr?

Chemistry
1 answer:
Pepsi [2]1 year ago
7 0

Answer:

3.5 yrs

Explanation:

If a sample has decayed to 25%, this means 2 half-lives have passed. We are given this is equal to 7 yrs, and it follows that one half life is 3.5 yrs.

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When should you<br> use a fume hood?
AfilCa [17]

Answer:

if you are working with hazardous materials.

Explanation:

A properly operating and correctly used fume hood can reduce or eliminate exposure to volatile liquids, dusts, and mists. It is advisable to use a laboratory hood when working with all hazardous substances.

4 0
3 years ago
Which process is caused by an increase in thermal energy
Over [174]

Answer:

They're different - heat and thermal energy. ... The heat, in turn, speeds up the molecules within the pot and the water. If you place a thermometer in the water, as the water heats up, you can watch the temperature rise. Again, an increase in internal energy will result in an increase in temperature.

8 0
3 years ago
Calculate the molality of 75.0 grams of MgCl2 (molar mass=95.21 g/mol) dissolved in 500.0 g of solvent.
nordsb [41]

<u>Answer:</u> The molality of magnesium chloride is 1.58 m

<u>Explanation:</u>

To calculate the molality of solution, we use the equation:

\text{Molality}=\frac{m_{solute}\times 1000}{M_{solute}\times W_{solvent}\text{ (in grams)}}

Where,

m_{solute} = Given mass of solute (magnesium chloride) = 75.0

M_{solute} = Molar mass of solute (magnesium chloride) = 95.21 g/mol  

W_{solvent} = Mass of solvent = 500.0 g

Putting values in above equation, we get:

\text{Molality of }MgCl_2=\frac{75.0\times 1000}{95.21\times 500.0}\\\\\text{Molality of }MgCl_2=1.58m

Hence, the molality of magnesium chloride is 1.58 m

5 0
3 years ago
Read 2 more answers
Sylvanite is a mineral that contains 28.0% gold by mass. How much sylvanite would you need to dig up to obtain 73.0 g of gold?
Scorpion4ik [409]

You would have to dig up 261 g of sylvanite.

Mass of sylvanite = 73.0 g Au × (100 g sylvanite/28.0 g Au) = <em>261 g</em> sylvanite.


3 0
3 years ago
Hey!<br> I need a simple connotation of how glowsticks glow.<br> Please and thank you.
LenaWriter [7]

Answer:

simple

Explanation:

The glow stick's outer plastic tube holds a solution of an oxalate ester and an electron-rich dye along with a glass vial filled with a hydrogen peroxide solution. ... Glow sticks light up when oxalate esters react with hydrogen peroxide to form a high-energy intermediate

5 0
1 year ago
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