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
Serga [27]
3 years ago
5

Determine the molality of an aqueous solution that is 15.5 percent urea by mass.

Chemistry
1 answer:
DaniilM [7]3 years ago
3 0

15.5% by mass is equivalent 15.5 g urea in 100 g solution or 155 g urea in 1 kg solution. <span>

<span>we know that molality = moles solute / kg solvent

<span>moles solute = 155 g / 60 g/mol = 2.58 moles urea

</span></span></span>

Since there are 155 g urea in 1000g solution, hence the solvent is 845 g or 0.845 kg

So:<span>
<span>molality = 2.58 / 0.845 = 3.06 m</span></span>

You might be interested in
In a neutral atom, the number of protons is always equal to what other part of the atom?
Licemer1 [7]

Answer:

b. The number of electrons

Explanation:

A "neutral atom" has a <u>neutral charge</u>. This means that <em>its charge is equal to </em><em>zero. </em>In order for the charges to cancel out each other, the atom's <em>positive charge should be equal to the negative charge. </em>These being said, the number of electrons<em> (negatively-charged)</em> is then equal to the number of protons <em>(positively-charged). </em>Those atoms which are not neutral are called <em>"ions."</em> This means that they either have more or less electrons than the protons.

7 0
2 years ago
Which statements describing chemical and nuclear reactions are true?
Arte-miy333 [17]

Answer:

What statements?

Explanation:

they both release harmful chemicals and can pollute the earth and destroy our ecosystems.

8 0
2 years ago
How many liters of oxygen gas, at standard
Karo-lina-s [1.5K]

Answer:

Explanation:

  • For the balanced reaction:

<em>4Fe(s) + 3O₂(g) → 2Fe₂O₃(s)​.</em>

It is clear that 4 mol of Fe react with 3 mol of O₂ to produce 2 mol of Fe₂O₃.

  • Firstly, we need to calculate the no. of moles of 35.8 grams of Fe metal:

no. of moles of Fe = mass/molar mass = (35.8 g)/(55.845 g/mol) = 0.64 mol.

  • Now, we can find the no. of moles of O₂ is needed to react with the proposed amount of Fe:

<em><u>Using cross multiplication:</u></em>

4 mol of Fe is needed to react with → 3 mol of O₂, from stichiometry.

0.64 mol of Fe is needed to react with → ??? mol of O₂.

∴ The no. of moles of O₂ needed = (3 mol)(0.64 mol)/(4 mol) = 0.48 mol.

  • Finally, we can get the volume of oxygen using the information:

<em>It is known that 1 mole of any gas occupies 22.4 L at standard P and T (STP).</em>

<em></em>

<em><u>Using cross multiplication:</u></em>

1 mol of O₂ occupies → 22.4 L, at STP conditions.

0.48 mol of O₂ occupies → ??? L.

∴ The no. of liters of O₂ = (0.48 mol)(22.4 L)/(1 mol) = 10.752 L.

5 0
3 years ago
Why is copper (i) sulfate Cu2So4^-2? not copper (ii)?
const2013 [10]
Copper (I) oxidation state is 1 Cu2So4
copper (II) oxidation state is +2 CuSo4
copper (i) also give up one electron so you need two of them to react with the sulfate ion (which has charge of -2)
and also all metallic ions have an multiple oxidation levels corresponding to the number of electrons they can exchange or loose
Hope this helps
5 0
3 years ago
Read 2 more answers
NEED HELP QUICKLY!!! How many moles are in each of the following?
oksano4ka [1.4K]

Answer: a. 0.26mol

b. 0.000479mol

c. 1.12mol

Explanation: Please see attachment for explanation

6 0
3 years ago
Other questions:
  • What acid has a dissociation constant of 4.57x10^-3
    14·1 answer
  • Which statements correctly define factors that contributed to the decline of the Roman Empire? Choose all answers that are corre
    12·2 answers
  • 2. Write a balanced chemical equation from the following descriptions.
    7·1 answer
  • How does the light source readout differ from the x-ray readout in the gizmo??
    11·1 answer
  • The combustion of 2.95 grams of a compound that contains only C, H and S yields 5.48
    8·1 answer
  • If you have a density of 100 kg/L and a mass of 1000 g what is the volume (please explain)
    13·1 answer
  • How many milliliters of 0.281 M NaCl solution must be measured to obtain 0.177 mol of NaCl?
    14·1 answer
  • For the reaction of nitric oxide and oxygen to form nitrogen dioxide, the reaction begins with 12.0 g of nitric oxide and 12.0 g
    6·1 answer
  • CaCO3 → CaO + CO2 Calculate the theoretical yield of Calcium Oxide if 24.8 grams of Calcium Carbonate decomposes. Calculate the
    11·1 answer
  • The average kinetic energy of a sample of water molecules is –
    7·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!