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valentinak56 [21]
3 years ago
8

A radioactive substance decays exponentially. a scientist begins with 120 milligrams of a radioactive substance. after 14 hours,

60 mg of the substance remains. how many milligrams will remain after 19 hours?
Chemistry
1 answer:
Yanka [14]3 years ago
4 0
First thing is you have to find the half life of the substance. The half life equation is
Final Mass = Initial Mass * 0.5^(time/time per half life)
Now we substitute the values given and we get
60 mg = 120 * 0.5^(14/t)
Solve for t and you get
t = 14 hours
Now plug 19 into the equation
Final Mass = 120 * 0.5^(19/14)
Final Mass = 46.84 mg
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What is the volume of the sphere? Round your answer<br> to the nearest tenth.<br> cm
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volume

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Explanation:

it isn't specific enough but that is the equation of how to get any volume

volume equals four thirds times pi times radios to the power of three

4 0
4 years ago
What is the net ionic equation for the reaction that occurs when aqueous solutions of koh and zncl2 are mixed?
Mademuasel [1]

Answer:

Net ionic equation:

Zn²⁺(aq)  +   2OH⁻(aq)     →    Zn(OH)₂(s)

Explanation:

Chemical equation:

ZnCl₂ + KOH    →   KCl  + Zn(OH)₂

Balanced chemical equation:

ZnCl₂ + 2KOH    →   2KCl  +Zn(OH)₂

Ionic equation;

Zn²⁺(aq)  + 2Cl⁻(aq)  + 2K⁺(aq)  +  2OH⁻(aq)     →   2K⁺(aq)  + 2Cl⁻(aq)   +Zn(OH)₂(s)

Net ionic equation:

Zn²⁺(aq)  +   2OH⁻(aq)     →    Zn(OH)₂(s)

The K⁺  and Cl⁻  are spectator ions that's why these are not written in net ionic equation. The  Zn(OH)₂ can not be splitted into ions because it is present in solid form.

Spectator ions:

These ions are same in both side of chemical reaction. These ions are cancel out. Their presence can not effect the equilibrium of reaction that's why these ions are omitted in net ionic equation.  

5 0
3 years ago
The electron cloud model describes the __of electrons in an atom.
Alex Ar [27]

Answer:

it's location

Explanation:

4 0
3 years ago
Can someone solve this for me I'm confused.
Artemon [7]

Answer:

310.53 g of Cu.

Explanation:

The balanced equation for the reaction is given below:

CuSO₄ + Zn —> ZnSO₄ + Cu

Next, we shall determine the mass of CuSO₄ that reacted and the mass Cu produced from the balanced equation. This can be obtained as follow:

Molar mass of CuSO₄ = 63.5 + 32 + (16×4)

= 63.5 + 32 + 64

= 159.5 g/mol

Mass of CuSO₄ from the balanced equation = 1 × 159.5 = 159.5 g

Molar mass of Cu = 63.5 g/mol

Mass of Cu from the balanced equation = 1 × 63.5 = 63.5 g

Summary:

From the balanced equation above,

159.5 g of CuSO₄ reacted to produce 63.5 g of Cu.

Finally, we shall determine the mass of Cu produced by the reaction of 780 g of CuSO₄. This can be obtained as follow:

From the balanced equation above,

159.5 g of CuSO₄ reacted to produce 63.5 g of Cu.

Therefore, 780 g of CuSO₄ will react to produce = (780 × 63.5)/159.5 = 310.53 g of Cu.

Thus, 310.53 g of Cu were obtained from the reaction.

6 0
3 years ago
Please help me out with this question if you help me I will give you the brain thing and extra points. 4/9 image below.
gayaneshka [121]

Answer:

It’s C

Explanation:

4 0
3 years ago
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