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
Sindrei [870]
3 years ago
9

A 115-g sample of steam at 100 °C is emitted from a volcano. It condenses, cools, and falls as snow at 0.0 °C. How many kilojoul

es were released?
Can someone please tell me how to do it step by step?
Chemistry
1 answer:
GarryVolchara [31]3 years ago
5 0

Answer:

∑Q(TTL) = 347 Kj. = 82.8 Kcal. (3 sig. figs.)

Explanation:

Draw a typical heating curve for water (see figure below) and label each section with data needed to calculate the amount of heat flow in the specified section.  

Super-imposing given data onto a trace of a typical heat flow chart for water finds there are three segments of the heating curve that can utilize the given data to calculate heat flow for each segment. With all three heat flow quantities, the total heat quantity associated with this problem is marked in orange. Calculate the heat quantity associated with the designated segments and add to obtain total heat flow for the transitions listed.  

Point E to D => Q₄ = m∙ΔHᵥ = (115g)(540 cal/g) = 62,100 cals.

Point D to C => Q₃ = m∙c∙ΔT = (115g)(1 cal/g∙˚C)(100˚C) = 11,500 cals.

Point C to B => Q₂ = m∙ΔHₓ = (115g)(80cal/g) = 9,200 cals.

Total Heat Flow (∑Qₙ) = Q₄ + Q₃ + Q₂ = 62,100 cals.  +  11,500 cals.  +  9,200 cals. = 82,800 cals.

= (82,800 cals.)(4.184 joules/cal.) = 346,435 joules = 346.435 Kj ~ 347 Kj (3 sig. figs.) _____________________________________________________

m = mass = 115g

c = specific heat of liquid water = 1 calorie/gram·°C = 4.184 j/g·°C

ΔT = temperature change in degrees Celsius

ΔHᵥ = heat of vaporization = 540 cals./gram

ΔHₓ = heat of crystallization = 80 cal./gram

Qₙ = heat flow quantity per specific segment (calories or joules)

∑Qₙ = total heat flow

Heating curve for water:

Note in the diagram that only two formulas are used.

Q = m·c·ΔT => heating or cooling the pure condensed state. The segments demonstrate temperature change.

Q = m·ΔHₙ => heat flow during phase change. Note, in these segments of the heating curve two phases are in contact. That is solid/liquid or liquid/gas phase substances. Also note, in these segments, when two phases are in contact no temperature change occurs. Examples, ice water remains at a constant temperature until all ice is melted or all of the liquid water is frozen depending upon the direction of heat flow. The same is true for boiling water in that when two phases are in contact (liquid/gas), temperature remains constant. The portions of the heating curve designating phase transitions are horizontal and are defined by the equation Q = m·ΔH,  while the curve segments that are only one phase demonstrate temperature change and are defined by the equation containing temperature change, Q = m·c·ΔT.  

You might be interested in
What is the boiling point of an aqueous solution that has a vapor pressure of 23.0 torr at 25 ∘C? (P∘H2O=23.78 torr; Kb= 0.512 ∘
UNO [17]

Answer:

Boiling point of the solution is 100.964°C

Explanation:

In this problem, first, you must use Raoult's law to calculate molality of the solution. When you find the molality you can obtain the boiling point elevation because of the effect of the solute in the solution (Colligative properties).

Using Raoult's law:

Psol = Xwater × P°water.

As vapour pressure of the solution is 23.0torr and for the pure water is 23.78torr:

23.0torr= Xwater × 23.78torr.

0.9672 = Xwater.

The mole fraction of water is:

0.9672 = \frac{X_{H_2O}}{X_{H_2O}+X_{solute}}

Also,

1 = X_{H_2O}+X_{solute}

You can assume moles of water are 0.9672 and moles of solute are 1- 0.9672 = 0.0328 moles

Molality is defined as the ratio between moles of solute (0.0328moles) and kg of solvent. kg of solvent are:

09672mol *\frac{18.01g}{1mol}* \frac{1kg}{1000g} = 0.01742kg

Molality of the solution is:

0.0328mol Solute / 0.01742kg = 1.883m

Boiling point elevation formula is:

ΔT = Kb×m×i

<em>Where ΔT is how many °C increase the boiling point regard to pure solvent, Kb is a constant (0.512°C/m for water), m molality (1.883m) and i is Van't Hoff factor (Assuming a i=1).</em>

Replacing:

ΔT = 0.512°C/m×1.882m×1

ΔT = 0.964°C

As the boiling point of water is 100°C,

<h3>Boiling point of the solution is 100.964°C</h3>

<em />

5 0
3 years ago
THIS HAS NOTHING TO DO WITH SCHOOL.
klio [65]

OMG yessss that is so cute she will totally accept

5 0
3 years ago
Read 2 more answers
Ca(OH)2 + H3PO4 = Ca3(PO4)2 + H2O
larisa [96]
Make a quick chart with each element represented, and count them up. HINT - leave the polyatomic anions together - in this case, PO4

Left      Right
1     Ca  3
2      O   1
5      H   2
1    PO4 2

Begin by balancing like finding common denominators of fractions - apply to both sides:
I started by adding a 2 in front of H3PO4 on the left, them 6 in front of H2O on the right. Last, a 3 in front of Ca (OH)2. Then, re-count using the chart format to make sure you're right.

3Ca(OH)2 + 2H3PO4 = Ca3(PO4)2 + 6H2O

4 0
3 years ago
BIOCHEMISTRY HELP! You and a lab partner are performing on several molecular analogs to determine Km. One is a substrate analog,
Alina [70]

Answer:

Michaelis constant is known as km which is the substrate concentration that encourages the compound to work at half maximum velocity represented by Vmax/2. Michaelis constant is inversely related to the substrate and the affinity of the enzyme.  

Induced fit model: The premise of the purported induced fit hypothesis, which expresses that the attachment or association of a substrate or some other atom to an enzyme causes an adjustment to the enzyme in order to fit or restrain its activity.  

In substrate, analog Km or Michaelis constant will be high as the substrate will stay because of analogs inhibit activity.

In the transitional state, analog Km will be in the middle of the substrate and product analogs. Progress state analogs are synthetic mixes with a structure catalyzed reaction that looks like the progressing condition of a substrate atom in a compound enzyme.  

In item simple thus Km is the least.  

0.0013 M = product ananlog,

0.025 M=Transition state, and

0.0045 M = Substrate analog

5 0
3 years ago
Can someone who expert in chemistry be my personal tutor? I'm so desperate​
lions [1.4K]
Yes..? I don’t understand what you’re trying to ask mate.
5 0
3 years ago
Other questions:
  • Which of the following statements is true concerning the reaction given below?2H2S(g) + O2(g) → 2S(s) + 2H2O(g)a. The reaction i
    11·1 answer
  • What is the total number of moles of hydrogen gas contained in 9.03 x 10^23 molecules
    5·2 answers
  • The bond energy for the van der waals bond between two helium atoms is 7.9×10−4ev. assuming that the average kinetic energy of a
    14·1 answer
  • This reaction forms triphenylmethanol from benzophenone. How could you use infrared spectroscopy to show that the benzophenone h
    5·1 answer
  • I NEED HELP PLEASE, THANKS! BRAINLIEST :)
    11·1 answer
  • What are the three types of CONSUMERS and how do they get their<br> energy? *
    10·1 answer
  • What are fossil fuels made from?
    11·2 answers
  • I need help with this ​
    11·1 answer
  • What is the color of the flame when magnesium burns in air ​
    8·1 answer
  • What is the overall charge on the compound, sodium hydroxide? explain
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!