A chemical change can also be called a chemical reaction
The simple trick which one can consider in such problem where it is asked for positron emission is :
<span>When the atomic number goes DOWN by one and mass number remains unchanged, then a positron is emitted.
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<span>a. </span>

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Here the atomic number decreases by one.
Similarly, options b and d are eliminated.
Option c is also not the answer.
For c, Count the atomic number on left side and compare it with right side. You will see it is 9 on left and 8 on right. Atomic no. did go down by 1. But the atomic mass is changed as well.
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36 divided by 12 is 3. you need three times as much of the recipe to make 36 brownies. The answer is B
Than you for posting your question here. I hope the answer helps.
The answer as to be grams (g) since you it is aske for mass. What you have for units is 1/g.
<span>Very close. The factor is 5. </span>
<span>answer is 5 * 65 g of water.</span>
Answer:
10. D
9. A
8. A or B
Explanation:
10. Calcium has 20 electrons, but the Calcium ion has 18 electrons.
9. The mass of electrons are negligible.
8. Electrons have a very small mass where some consider it to have no mass.