0.139 moles of plutonium are present in a sample containing 8.4 x 10²² atoms of Pt.
<h3>How to calculate number of moles?</h3>
The number of moles of a substance can be calculated using the following expression:
no of moles = no of molecules ÷ 6.02 × 10²³
According to this question, 8.4 × 10²² atoms of plutonium are present in the molecule of plutonium.
no of moles = 8.4 × 10²² = 6.02 × 10²³
no of moles = 1.39 × 10-¹
no of moles = 0.139moles
Therefore, 0.139 moles of plutonium are present in a sample containing 8.4 x 10²² atoms of Pt.
Learn more about no of moles at: brainly.com/question/14919968
#SPJ1
B. It does not change the chemical composition of water.
Basically, ice is water before it became ice. So basically, it just returned to it's original state and form.
Answer:
Explanation:
When water changes from ice (solid) to water (liquid), it is melting or fusion. Therefore, we can use the following formula to find energy:
where <em>q</em> is the energy, <em>m </em>is the mass, and <em>Hf</em> is the heat of fusion.
1. Define Values
The mass is 150 grams. The heat of fusion for water is 334 Joules per gram.
2. Calculate Energy
Substitute the values into the formula.
Multiply. Note that the grams (g) will cancel each other out and leave Joules as our units.
3. Convert Units
We found the answer in joules, but the question asks for kilojoules, so we must convert.
There are 1000 Joules in 1 kilojoule. Therefore, we can divide the joules calculated by 1000.
<u>50.1 kilojoules </u>are needed to change 150 grams of ice to water.
None of the above.
1 mole filled with gas at STP occupies
=22.4 L
∴ 3mole of kr gas at STP occupies
= 3 × 22.4
= 67.2 L