Answer:
0.42 g
Explanation:
<u>We have: </u>
pH = 12.10 (25 °C)
V = 800.0 mL = 0.800 L
To find the mass of sodium hydroxide (NaOH) we can use the pH:


![pOH = -log ([OH^{-}])](https://tex.z-dn.net/?f=%20pOH%20%3D%20-log%20%28%5BOH%5E%7B-%7D%5D%29%20)
![[OH]^{-} = 10^{-pOH} = 10^{-1.90} = 0.013 M](https://tex.z-dn.net/?f=%5BOH%5D%5E%7B-%7D%20%3D%2010%5E%7B-pOH%7D%20%3D%2010%5E%7B-1.90%7D%20%3D%200.013%20M)
Now, we can find the number of moles (η) of OH:
Since we have 1 mol of OH in 1 mol of NaOH, the number of moles of NaOH is equal to 1.04x10⁻² moles.
Finally, with the number of moles we can find the mass of NaOH:

<em>Where M is the molar mass of NaOH = 39.9 g/mol </em>

Therefore, the mass of sodium hydroxide that the chemist must weigh out in the second step is 0.42 g.
I hope it helps you!
In a system, heat that is gained and lost should be conserved. We calculate as follows:
Heat from phase change + sensible heat from the change in tempeture of the ice = sensible heat from the change in temperature of water
mH(fusion) + mCpΔT = mCpΔT
.05 (335) + .050(4.184)( T - 0) = .4 (4.184)(45 - T)
T = 34.8 °C
Answer:
Explanation:
Cyanobacteria, also known as blue-green algae, are a kind of bacteria found in many lakes. These organisms make their own food through photosynthesis. Small animals, including mayfly larvae, eat the cyanobacteria. ... The small fish provide food for larger fish, such as walleye.
Answer:
V = 365.54 mL
Explanation:
Given that,
The density of chloroform, d = 1.48 g/mL
The mass of chloroform, m = 541 g
We need to find the volume of chloroform.
We know that,
Density = mass/volume
So,

So, the volume of chloroform is 365.54 mL.