C = 12 g
O = 16 g
H = 1 g
<h3>Further explanation
</h3>
Conservation of mass stated that
<em>In a closed system, the masses before and after the reaction are the same
</em>
we can calculate the mass of each atom in the compound :
O in O₂ :
mass O₂ = 32
mass O = 32 : 2 = 16 g
H in H₂O
mass H₂O = 18
mass 2.H + mass O = 18
mass 2.H + 16 = 18
mass 2.H=2
mass H = 1 g
C in CH₄
mass CH₄ = 16
mass C + mass 4.H = 16
mass C + 4.1=16
mass C = 12 g
or we can use formula :
Mass of a single C :

I think it’s A but I’m not sure. Sorry if I’m wrong
<u>Answer:</u> The amount of sample left after 20 years is 288.522 g and after 50 years is 144.26 g
<u>Explanation:</u>
We are given a function that calculates the amount of sample remaining after 't' years, which is:

Putting values in above equation:


Hence, the amount of sample left after 20 years is 288.522 g
Putting values in above equation:


Hence, the amount of sample left after 50 years is 144.26 g
1.51 x 10²⁵atoms
Explanation:
Given parameters:
Mass of Na = 578g
Unknown:
Number of atoms = ?
Solution:
To find the number of atoms, we must first find the number of moles the given mass contains.
Number of moles = 
molar mass of Na = 23g
Number of moles =
= 25.13moles
1 mole of a substance = 6.02 x 10²³atoms
25.13 mole of Na = 25.13 x 6.02 x 10²³atoms
This gives 1.51 x 10²⁵atoms of Na
Learn more:
Avogadro's constant brainly.com/question/2746374
#learnwithBrainly
Answer:
Cl
Explanation:
chlorine (2,8,7) is a non metal with highest electronegativity. Hence, it is most likely to form a negative ion with charge −1.
I hope it helps you