Answer:
0.77 M
Explanation:
Molarity is the concentration of a solution per liter
C= concentration
n= number of moles
V= volume of solution
The formula we will use is C= n/V
C= n/V
C= (1.93 mol NaCl)/(2.5 L of solution)
C= 0.772 mol/L
Since this concentration is given in moles per liters of a solution, this concentration is also the molarity.
C= 0.772 mol/L
*Include two significant digits in final answer*
M= 0.77 M
When Ksp = [A2+] [S2-]
when A is the metal: Fe, Ni, Pb, and Cu
When we have [S2-] = 0.1 m and we have Ksp for each metal So by substitution in Ksp formula we can get [A2+] for each metal and compare its value with solution concentration 0.01 M, when we have a concentration more than 0.01 M So there are no sulfides precipitates
- [Fe2+] = Ksp/[S2-]
by substitution with Fe2+ Ksp value:
= 6x10^2 / 0.1
= 6x10^3 M
when [Fe2+] > 0.01 M
∴ no precipitate- [Ni2+] = Ksp /[S2-]
by sustitution with Ni Ksp value :
= 8x10^-1 / 0.1
= 8 M
When [Ni2+] > 0.01 M
∴ no precipitate-[Pb2+] = Ksp / [S2-]
by substitution with Pb Ksp value:
= 6x10^-7 / 0.1
= 6 x 10^-6 M
when [Pb2+] < 0.01 M
∴PbS will be precipited-[Cu2+] = Ksp / [S2-]
by substitution with Cu2+ Ksp value:
= 6x10^-16 / 0.1
= 6x10^-15 M
when [Cu2+] < 0.01 M
∴ CuS will be precipited∴The sulfides precipitates are CuS & PbS
The answer is choice (1).
In case you're interested in the solution for future reference:
-- Density = (mass) / (volume)
-- The scale shows that the mass of the sample is 60 grams.
-- The graduated cylinder has 24 mL in it <em>without</em> the sample.
The graduated cylinder has 34 mL in it <em>with</em> the sample.
The volume of the sample is (34mL - 24mL) = 10 mL .
-- Density = mass/volume = 60g / 10mL = 6 g/mL
Answer:
B. CH3CH2OH
Explanation:
Ethanol has a chemical formula of CH3CH2OH, it is the second member of the series in the alkanol family. Ethanol is a colourless, volatile liquid with a characteristic smell and taste. It is readily soluble in water in all proportions. It has a boiling point of 78° C. The physical properties such as the solubility of alkanols are affected by the presence of hydrogen bonding. The hydroxyl group is capable of bonding to other alkanol molecules. The boiling points rise with increasing molecular mass.
Hydrogen bonding helps the molecules to stick together. For example comparing the boiling point of pentane ( 36° C) with that of butan-1-ol (118° C) , the boiling point of alkanol is much higher even though the two compound are of similar relative molecular mass. This is due to the presence of hydrogen bonds in butanol.
Hydrocarbons are not soluble in water but alkanols are soluble in water because of the hydroxyl groups in the molecules can form hydrogen bond with water. Solubility of alkanol in water decreases as the number of carbon atom increases. Primary alcohol with more than five carbon atoms are insoluble in water.