1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
NemiM [27]
3 years ago
15

You dissolve the sample of fd&c red 40 (molar mass 496.4200 g/mol) in enough water to make 250.0 ml of solution. we call thi

s the stock solution. what is the concentration of the stock solution in terms of molarity?
Chemistry
1 answer:
icang [17]3 years ago
8 0
Molar mass 496.4200 g/mol

Number of moles:

40 g x 1 mol / 496.4200 => 0.08057 moles

Volume in liters:

250.0 mL / 1000 => 0.25 L

Therefore:

M = moles / V

M = 0.08057 / 0.25

 = 0.32228 M

hope this helps!
You might be interested in
The charge on a magnesium ion is +2. When it formed an ionic compound with another element, it lost
strojnjashka [21]
I believe it’s loses two electrons.
4 0
2 years ago
What has the lowest boiling point
Ratling [72]
Helium is the lowest boiling point.
5 0
3 years ago
Read 2 more answers
How do you determine the chemical reactivity for metals by using the periodic table?
vesna_86 [32]

Answer:

Chemical reactivity increases down a group and decreases from left to right of a period.

Explanation:

The higher the ionization energy is, the lower the reactivity is. Since the ionization energy is highest in the top right corner of the periodic table, we can assume that the most reactive elements are in the opposite bottom left corner. This is because the electrons that react are farther away from the nucleus thus experience less attraction to the nucleus (called nuclear shielding). Therefore their electrons are more easily removed than elements that don't ecperience nuclear shielding.

4 0
3 years ago
What is the pH at the equivalence point in the titration of a 25.7 mL sample of a 0.370 M aqueous nitrous acid solution with a 0
expeople1 [14]

Answer:

pH = 8.24

Explanation:

Nitrous acid (HNO₂) reacts with KOH, thus:

HNO₂ + KOH → KNO₂ + H₂O

Moles of HNO₂ are:

0.0257mL ₓ (0.370mol / L) = 0.00951moles.

In equivalence point, the complete moles of nitrous acid reacts with KOH producing potassium nitrite. There are needed:

0.00951mol ₓ (1L / 0.491mol) = 0.01937L ≡ 19.4mL of 0.491M KOH to reach equivalence point.

Total volume in equivalence point is: 19.4mL + 25.7mL = <em>45.1mL</em>

Potassium nitrite is in equilibrium with water, thus:

NO₂⁻ + H₂O ⇄ HNO₂ + OH⁻

Where equilibrium constant, Kb, is defined as:

Kb = 1.41x10⁻¹¹ = \frac{[OH^-][HNO_2]}{[NO_2]}

In equilibrium, molarity of each compound are:

[NO₂⁻]: 0.00951mol/0.00451L - X = 0.211M - X

[HNO₂]: X

[OH⁻]: X

<em>Where X is reaction coordinate</em>

Replacing in Kb:

1.41x10⁻¹¹ = \frac{[X][X]}{[0.211 -X]}

0 = X² + 1.41x10⁻¹¹X - 2.97x10⁻¹²

Solving for X:

X = -1.72x10⁻⁶ <em>FALSE ANSWER. There is no negative concentrations.</em>

X = 1.72x10⁻⁶. <em>Right answer.</em>

That means:

[OH⁻]: 1.72x10⁻⁶M

As pOH is -log [OH⁻] and pH = 14-pOH:

pOH = 5.76; <em>pH = 8.24</em>

3 0
3 years ago
Maltase is an enzyme that breaks down maltose. If a maltase enzyme has just completed catalyzing the decomposition of maltose, t
netineya [11]
Yes it is available. It will continue catalyzing the reactions until it becomes completely consumed. That's how enzymes work. They work and are eventually consumed in the process completely without altering the reaction in any way other than speeding it up.
<span />
7 0
3 years ago
Other questions:
  • A woman informs her engineer husband that "hot water will freeze faster than cold water." He calls this statement nonsense but h
    10·1 answer
  • Which colorless and odorless gas, produced by radioactive decay of uranium-238, is considered to be a form of pollution?
    13·1 answer
  • Which type of energy would have nothing to do with ironing clothes?
    10·2 answers
  • Propose a mechanism to account for the formation of a cyclic acetal from 4-hydroxypentanal and one equivalent of methanol. If th
    15·1 answer
  • Choose all the correct information concerning chemical reactions: Involves small amounts of energy. Some of the mass is converte
    14·2 answers
  • Aqueous solutions of hydrochloric acid and barium hydroxide can neutralize each other to produce a compound that is soluble in w
    12·1 answer
  • C= 51.89% H= 9.82% Br=38.29%
    5·1 answer
  • As atoms get smaller,valance electrons are getting closer or farther away?
    13·2 answers
  • Ammonia reacts with fluorine gas according to the thermochemical equation given
    14·2 answers
  • Help!!!!!!please it’s due tonight
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!