Answer:
See explanation
Explanation:
All the substances in the mixture; sodium chloride ,lead II oxide and iron filings are solids.
The first step is to use a magnet to separate the iron fillings which is a magnetizable material.
The remaining part of the mixture is now dissolved in water. Lead II oxide is insoluble in water while sodium chloride is very soluble in water hence a filtrate and a residue are obtained.
The residue is lead II oxide which can be dried to recover the solid. The filtrate contains sodium chloride which is recovered by evaporating the solution to dryness.
4.48
pH=pKa+log([A-/HA])
25% deprotonated tells us that A- is .25 and that the rest (75% is protonated) thats .75.
4 = pKa + log \frac{.25}{.75}
4 - log \frac{.25}{.75} = pKa
4.48=pKa
Molarity is the amount of solute molecule (in moles) per 1L of solvent. In this case, the solute is 0.7mol Na2S and the solvent volume is 1.05L. Since the unit in this problem is already mol and L then you don't need to do any conversion of the units. The calculation would be:
molarity = mol of solute / (1L/ volume of solvent)
molarity = 0.7 mol/ (1L/ 1.05L)= 0.67M
Answer:
The third option
Explanation:
If people have found more volcanic rock layers in the past that would mean that volcanic activity was more common in the past.