The correct answer is d) methane (

)
The other options are elements.
Answer:
8.547 x 10⁴disintegrations per second
Explanation:
To calculate the disintegrations per second as -
Given ,
2.31 μCi of sulfur -35 .
Since ,
1 Ci = 3.7 * 10 ¹⁰ Bq
1 μCi = 10 ⁻⁶ Ci
Hence ,
conversation is done as follows -
2.31 ( 1 * 10⁻⁶) * ( 3.7 * 10¹⁰)
= 8.547 x 10⁴
Hence ,
8.547 x 10⁴disintegrations per second , the sample undergo for it to be brand new .
Answer:
The correct answer is option B
Explanation:

Given values,
Molarity of 
Volume of solution, 
Molecular weight of 
Substituting this values in Molarity formula, we get

The process that is physical changes is:
- mixing frozen orange juice concentrate with water
<h3>What is a physical change?</h3>
A physical change can be described as a type of change that take place in physical without chemical reaction as opposed to chemical change.
They are changes that are usually reversible it should be noted that physical change do not involve the alterations as regards the chemical make up of a particular substance and as a result of this , in physical change, there is no formation of new product.
Therefore, The process that is physical changes is mixing frozen orange juice concentrate with water
Read more about physical changes here:
brainly.com/question/13056570
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