Use PV=nRT to solve the equation. You need to solve for n (number of moles). Don’t forget to convert the temperature to kelvins by adding 25+273. Use 0.082057 for R.
Answer : The volume of 3.0 M spinach solution added should be, 50 mL
Explanation :
Formula used :

where,
are the initial molarity and volume of spinach solution.
are the final molarity and volume of diluted spinach solution.
We are given:

Now put all the given values in above equation, we get:

Hence, the volume of 3.0 M spinach solution added should be, 50 mL
Hey
Sorry, But There Is No 7th Element in group two. only six which is Radium.
~Spades15
Answer: 72 grams of
are needed to completely burn 19.7 g 
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number
of particles.
To calculate the number of moles, we use the equation:

Putting in the values we get:


According to stoichiometry:
1 mole of
requires 5 moles of oxygen
0.45 moles of
require=
moles of oxygen
Mass of 
72 grams of
are needed to completely burn 19.7 g 