Explanation:
When water vapour changes to liquid water then this process is known as condensation.
For example, when lid is placed in a hot water filled pan then after sometime vapours appear on the surface of lid. When temperature of water decreases then water vapours convert into liquid form.
Thus, we can conclude that in condensation water vapor changes to liquid water.
<u>Answer:</u> The number of carbon and oxygen atoms in the given amount of carbon dioxide is 
and 
respectively
<u>Explanation:</u>
To calculate the number of moles, we use the equation:
Given mass of carbon dioxide gas = 3.45 g
Molar mass of carbon dioxide gas = 44 g/mol
Putting values in above equation, we get:
1 mole of carbon dioxide gas contains 1 mole of carbon and 2 moles of oxygen atoms.
According to mole concept:
1 mole of a compound contains 
number of molecules
So, 0.0784 moles of carbon dioxide gas will contain 
number of carbon atoms and 
number of oxygen atoms
Hence, the number of carbon and oxygen atoms in the given amount of carbon dioxide is and respectively
Answer:12.5
Explanation: Divide 50$ by the 4 hours and you will get 12.5 which is $12.50.
Answer:
b. 54.9%
Explanation:
An emerald gemstone has the formula Be₃Al₂Si₁₆O₁₈. We can find the mass of each element in 1 mole of Be₃Al₂Si₁₆O₁₈ by multiplying the molar mass of the element by its atomicity.
Be: 3 × 9.01 g = 27.03 g
Al: 2 × 26.98 g = 53.96 g
Si: 16 × 28.09 g = 449.4 g
O: 18 × 16.00 g = 288.0 g
Total mass = 818.4 g
The mass percentage of silicon is:
(449.4 g / 818.4 g) × 100% = 54.91%
