Ok I may be young but combine the two reactions to create a compund
7.86 is the pOH of water at this temperature of 100 degrees celsius.
Option E is the right answer.
Explanation:
Data given:
Kw = 51.3 x 
pOH = ?
we know that pure water is neutral and will have pH pf 7.
The equation for relation between Kw and H+ and OH- ion is given by:
Kw = [H+] [OH-}
here the concentration of H+ ion and OH- ion is equal
so, [H+]= [OH-]
Putting the values in the equation of Kw
pKw = -log[Kw]
pKw = -log [51.3 x
]
pKw = 12.28
since H+ ion OH ion concentration is equal the pH of water is half i.e. 6.14
Now, pOH is calculated by using the equation:
14 = pOH + pH
14- 6.14 = pOH
pOH = 7.86
Answer:
The atomic mass of gallium (Ga) = <u>69.723 g/mol</u>
Explanation:
Given: Two isotopes of Gallium (Ga) are Gallium-69 (⁶⁹Ga) and Gallium-71 (⁷¹Ga)
<u>For ⁶⁹Ga: </u>
Relative abundance = 60.12% = 60.12 ÷ 100 = 0.6012; Atomic mass = 68.9257 g/mol
<u>For ⁷¹Ga:</u>
Relative abundance = 39.88% = 39.88 ÷ 100 = 0.3988; Atomic mass = 70.9249 g/mol
∴ The atomic mass of Ga = (Relative abundance of ⁶⁹Ga × Atomic mass of ⁶⁹Ga) + (Relative abundance of ⁷¹Ga × Atomic mass of ⁷¹Ga)
⇒ Atomic mass of Ga = (0.6012 × 68.9257 g/mol) + (0.3988 × 70.9249 g/mol) = <u>69.723 g/mol</u>
<u>Therefore, the atomic mass of gallium (Ga) = 69.723 g/mol</u>
Answer : The mass of the water in two significant figures is, 
Explanation :
In this case the heat given by the hot body is equal to the heat taken by the cold body.


where,
= specific heat of iron metal = 
= specific heat of water = 
= mass of iron metal = 32.3 g
= mass of water = ?
= final temperature of mixture = 
= initial temperature of iron metal = 
= initial temperature of water = 
Now put all the given values in the above formula, we get


Therefore, the mass of the water in two significant figures is, 