The answer is hydrogen (H2) because i just answered this question from Edgenuit.
 
        
             
        
        
        
1st one= CaO +H2O=Ca(OH)2
product side-
Ca=1
O=2
H=2
Reactant side-
Ca=1
O=2
H=2
The first one is balanced for you 
There is 1 calcium on each side 2 oxygens on each side and 2 hydrogens on each side
        
             
        
        
        
Answer:
Total pressure = 4.57 atm
Explanation:
Given data:
Partial pressure of nitrogen = 1.3 atm
Partial pressure of oxygen = 1824 mmHg
Partial pressure of carbon dioxide = 247 torr
Partial pressure of argon = 0.015 atm
Partial pressure of water vapor = 53.69 kpa
Total pressure = ?
Solution:
First of all we convert the units other into atm.
Partial pressure of oxygen = 1824 mmHg / 760 = 2.4 atm
Partial pressure of carbon dioxide = 247 torr / 760 = 0.325 atm
Partial pressure of water vapor = 53.69 kpa / 101 = 0.53 atm
Total pressure = Partial pressure of N +  Partial pressure of O +  Partial pressure of CO₂ +  Partial pressure of Ar +  Partial pressure of water vapor
Total pressure = 1.3 atm + 2.4 atm + 0.325 atm + 0.015 atm + 0.53 atm
Total pressure = 4.57 atm
 
        
             
        
        
        
Answer:
The brain is arguably the most important organ in the human body. It controls and coordinates actions and reactions, allows us to think and feel, and enables us to have memories and feelings—all the things that make us human.
Explanation:
 
        
                    
             
        
        
        
Answer:

Explanation:
You don't give the reaction, but we can get by just by balancing atoms of Na.
We know we will need the partially balanced equation with masses, moles, and molar masses, so let’s gather all the information in one place.
M_r:                                 142.04  
              2NaOH + … ⟶ Na₂SO₄ + …  
n/mol:      0.75
1. Use the molar ratio of Na₂SO₄ to NaOH to calculate the moles of NaF.
Moles of Na₂SO₄ = 0.75 mol NaOH × (1 mol Na₂SO₄/2 mol NaOH
= 0.375 mol Na₂SO₄
2. Use the molar mass of Na₂SO₄ to calculate the mass of Na₂SO₄.
Mass of Na₂SO₄ = 0.375 mol Na₂SO₄ × (142.04 g Na₂SO₄/1 mol Na₂SO₄) = 53 g Na₂SO₄
The reaction produces  of Na₂SO₄.
 of Na₂SO₄.