Answer:
1.15 atm
Explanation: 
According to Dalton's law of partial pressures, the total pressure is the sum of all the partial pressures of the gases present in the mixture.
Therefore we have:
Total pressure = partial pressure of carbon monoxide + partial pressure of oxygen + partial pressure of carbon dioxide
We were given the following:
Total pressure = 2.45 atm
Pressure of oxygen = 0.65 atm
Pressure of carbon monoxide = x
Pressure of carbon dioxide = 0.65 atm
Therefore:
2.45 = x + 0.65 + 0.65
2.45 = x + 1.3
x = 2.45 - 1.3
x = 1.15 atm
 
        
             
        
        
        
6.9 x 10^-4 would be .00069 written in scientific notation
        
                    
             
        
        
        
Answer : The final equilibrium temperature of the water and iron is, 537.12 K
Explanation :
In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.


where,
 = specific heat of iron =  560 J/(kg.K)
 = specific heat of iron =  560 J/(kg.K)
 = specific heat of water = 4186 J/(kg.K)
 = specific heat of water = 4186 J/(kg.K)
 = mass of iron = 825 g
 = mass of iron = 825 g
 = mass of water = 40 g
 = mass of water = 40 g
 = final temperature of water and iron = ?
 = final temperature of water and iron = ?
 = initial temperature of iron =
 = initial temperature of iron = 
 = initial temperature of water =
 = initial temperature of water = 
Now put all the given values in the above formula, we get:


Therefore, the final equilibrium temperature of the water and iron is, 537.12 K