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2 years ago

Lawrencium-262 has a half-life of 4 hr. How much of a 40 mg sample remains after 12 hours?

Chemistry

1 answer:

CaHeK987 [17]2 years ago

3 0

Answer:

5 mg

Explanation:

If one half life is 4 hours, then 3 half lives is 12 hours.

This means that the sample will decay to 1/8 of its original amount.

So, the answer is 40(1/8) = 5 mg.

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Which groups on the periodic table contain metalloids?

nasty-shy [4]

C. Groups 13-16 contain metalloids.

If you look on a periodic table, these usually have a different color.

3 0

3 years ago

Read 2 more answers

1. 2.0 mL/s x 4.0 hrs = ? L<br><br> How do you do this conversion problem

Phantasy [73]

Answer:

29 L.

Explanation:

Hello!

In this case, considering that we are performing a conversion by which the time should be cancelled out to obtain liters, we first need to convert the seconds on bottom to hours and then the volume on top to liters, just a shown down below:

$2.0\frac{mL}{s} *\frac{1L}{1000mL} *\frac{3600s}{1hr}*4.0hr\\\\=28.8L$

Which turns out 29 L with 2 significant figures.

Best regards!

6 0

3 years ago

What would be the total volume of the new solution when it is changed from 0.2 M to 0.04 M?

34kurt

The question is incomplete.

You need two additional data:

1) the original volume
2) what solution you added to change the volume.

This is a molarity problem, so remember molarity definition and formula:

M = n / V in liters: number of moles per liter of solution

To give you the key to answer this kind of questions, supppose the original volumen was 1 ml and that you added only water (solvent).

The original solution was:

V= 1 ml
M = 0.2 M

Using the formula for molarity, M = n / V

n = M×V = 0.2 M × (1 / 10000)l = 0.0002 moles

For the final solution:

n = 0.0002 moles
M = 0.04

From M = n / V ⇒ V = n / M = 0.002 moles / 0.04 M = 0.05 l

Change to ml ⇒ 0.05 l × 1000 ml / l = 50 ml. This would be the answer for the hypothetical problem that I assumed for you.

I hope this gives you all the cues you need to answer similar problems about molarity.

6 0

3 years ago

Read 2 more answers

In stomach, Hydrochloric acid kills micro-organisms in the food. Stomach juices begin to break down p to amino acids. Stomach ju

Butoxors [25]

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Inside the stomach, Hydrochloric acid kills micro-organisms in the food. Stomach juices begin to break down <u>proteins</u> to amino acids.

✤ So, Fill the blank with proteins.

<h3><u>Explanation:-</u></h3>

Inside the stomach, the digestion of proteins starts due to the action of pepsin enzyme.
But this enzyme remains inactive and is activated by the Hydrochloric acid(HCl).
The Hydrochloric acid also helps in killing the germs and microbes which entered along with food.
The mucous lines the wall of stomach to protect it from the harm caused by HCl because HCl is a strong acid.
In stomach, The partial digestion of proteins occur and rest is digested in the small intestine by Trypsin(Pancreatic enzyme) and Intestinal juices.

<u>━━━━━━━━━━━━━━━━━━━━</u>

6 0

3 years ago

Is matter smooth and continuous?

Strike441 [17]

Answer:

Explanation:

<h2><u><em> Matter is smooth and continuous. ... A liquid has a definite volume; but it has no definite shape.</em></u></h2>

3 0

3 years ago