Chemistry is defined as:

What is the correct formula for calcium sulfate dihydrate?

Murljashka [212]

Answer:

It is CaSO4.2H2O

Explanation:

Calcium has a valence of 2 because it has only two valency electrons.

Sulphate ( SO4)^2- is a radical with a valence value of 2.

When Calcium combines with sulphate in bonding,

Formular ==>  Ca2(SO4)2

But the 2 cancel out.

Overall formular==> CaSO4

For hydrated, ==> CaSO4.H2O

3 0

4 years ago

Write the balanced decomposition reaction of the hypochlorite ion into the chlorate and chloride ions using the smallest integer

Alja [10]

This is a redox reaction:

2OCl- --> ClO2- + Cl-

3 0

3 years ago

50 pennies or other coins (all coins must be the same value)

Neko [114]

Hey!

Hope this helps...

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Question 1: Turn 25 coins tails up. You now have 50% parent material and 50% daughter material. What is the half life of this substance? (20 Points)

Answer:

Based upon the given information, we can assume that the half life of this coin material is 5 years.

Question 2: Imagine that another half life has gone by. Remember that ONLY the parent material can change to the daughter material. Turn over your pennies to represent the passing of another half life. How much total parent material and how much total daughter material do you now have? You may express your answer in number of pennies or in %. (Note: Since you cannot turn over half a penny, round the actual number of pennies you would turn over up.) (20 points)

Answer:

Based upon the given information from Question 2 and Question 3, we can assume that 13 additional coins would be turned over. We started with 50, than flipped 50% of them over, and now another 50% over. We have 12 coins left.

Question 3: How many half lives will pass before you have only 3 pennies that are parent material and 47 pennies that are daughter material? (20 Points)

Answer:

Based upon the given information from all the questions, and based upon our answers we can assume this:

1st half-life: 50 turned to 25 coins

2nd half-life: 25 turned to 12 coins

3rd half-life: 12 turns to 6 coins

4th half-life: 6 turns to 3 coins

So, after 4 half-lives (or after 20 years) we would have 3 coins left that have parent material.

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For future reference please do not post as complex questions like this, if you do (post a question that is similar to this) please state the following information:

"All questions posted in this post relate to one-another and cannot be answered without the other questions..."

4 0

3 years ago

.

Mila [183]

Answer:

Explanation:

Half life of Nobelium-253 is 97 seconds . That means after every 97 seconds half of the Nobelium amount will be disintegrated .

Time taken in bringing the sample to laboratory = 291 seconds

291 second = 291 / 97 half life

n = 3

N = $N_0 (\frac{1}{2})^n$

N₀ is original mass , N is mass after n number of half life.

N = 5 mg x $(\frac{1}{2})^3$

= .625 mg

Only 0.625 mg of Nobelium-253 will be left .

7 0

3 years ago

Which statement best describes the effect of radioactive decay on a nucleus?

KATRIN_1 [288]

When radioactive decay occurs, the original nucleus splits into daughter nuclei and the resulting nucleus is more stable than the original nucleus. The nucleus can be of a different element than the original.

Unstable nuclei often undergo radioactive decay. In a radioactive decay, the unstable nucleus is broken up into other nuclei. Usually, the nuclei formed during radioactive decay are smaller in mass compared to the original nucleus.

Also, the resulting nucleus is more stable than the original nucleus. The nucleus can be of a different element than the original.

7 0

3 years ago

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