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
ycow [4]
3 years ago
13

A coffee-cup calorimeter initially contains 125 g water at 24.28C. Potassium bromide (10.5 g), also at 24.28C, is added to the w

ater, and after the KBr dissolves, the final temperature is 21.18C. Calculate the enthalpy change for dissolving the salt in J/g and kJ/mol. Assume that the specific heat capacity of the solution is 4.18 J/8C
Chemistry
1 answer:
iren2701 [21]3 years ago
6 0

Answer:

The solution is given below

Explanation:

Heat, q= mc∆T

q= 125g x 4.18 J/g∙°C x (21.18x- 24.28) °C

q=  -1619.75J

NEGATIVE SIGN INDICATES THAT HEAT IS ABSORBED.

Enthalpy Change, ∆H = 1619.75 7/ 10.5 g

                                     = 154.26 J/g

No. of moles of KBr = Mass of KBr/ Molecular Weight of KBr

                                =10.5g/119gmol-1

                                =0.088 mol

∆H= 1619.75 J/ 0.088 mol

      = 18.41 kJ/mol  

You might be interested in
Consider two different ions. The anion has a valence of -2. The cation has a valence of +2. The two ions are separated by a dist
strojnjashka [21]

Answer:

Force of attraction = 35.96 \times 10^{27}N

Explanation:

Given: charge on anion = -2

Charge on cation = +2

Distance = 1 nm = 10^{-9} m

To calculate: Force of attraction.

Solution: The force of attraction is calculated by using equation,

F = \dfrac{k \times q_1 q_2}{ \r^2} ---(1)

where, q represents the charge and the subscripts 1 and 2 represents cation and anion.

k = 8.99 \times 10^9 \ Nm^{2}C^{-2}

F = force of attraction

r = distance between ions.

Substituting all the values in the equation (1) the equation becomes

F = \dfrac{8.99 \times 10^9 \times 2 \times 2}{ \left ( 10^-9 \right )^2 }

Force of attraction = 35.96 \times 10^{27}N

6 0
3 years ago
One mole of calcium ions has the same number of representative particles as which of the following? one mole of calcium nuclei o
Kruka [31]
One mole is always the same number: 6.02 * 10^ 23.

So, one mole of cars = 6.02 * 10 ^23 cars; one mole of pencils = 6.02 * 10^23 pencils; one mole of atoms = 6.02 * 10^23 atoms; one mole of molecules = 6.02 * 10^23 molecules.

So, all the options are correct: one mole of calcium ions has 6.02 * 10^23 representative particles, such as one mole of calcium nuclei and one of calcium atoms.
3 0
3 years ago
Almost all of the energy on the surface of earth come from what
Rashid [163]
The sun solar energy produce all the energy
7 0
3 years ago
Read 2 more answers
ANSWER ASAP AND I WILL GIVE BRAINLYEST!!!!
Vlada [557]

Answer:

20m

Explanation:

mark brainliest

6 0
3 years ago
Katrina tried to take pictures with her cell phone but discovered that its battery was dead. What happened to the battery?
Aleks04 [339]
C. All the energy stored in the battery had been transformed.
4 0
2 years ago
Read 2 more answers
Other questions:
  • Nitrous oxide is used as an anesthetic. The pressure on 2.50 L of N2O changes from 105 kPa to 40.5 kPa. If the temperature does
    14·1 answer
  • the curved movement of air or water is the result of which of these. A).Winds speeding off equater B).the rotation of earth on i
    8·2 answers
  • Which states of matter have particles that move independently of one another with very little attraction?
    10·2 answers
  • What is the definition of physical science?
    12·2 answers
  • The chemical equation below summarizes cellular respiration. 6O2 + C6H12O6 à 6CO2 + 6H2O + energy The energy that is released by
    8·2 answers
  • Sketch the titration curve for the titration of a generic weak base B with a strong acid. The titration reaction is
    6·1 answer
  • Why does an ice cube melt when you hold it in your hand?
    11·2 answers
  • PLEASE HELP ME!!!!!!!!!!!!!!!!!!!
    14·1 answer
  • Why does such a small decrease in pH mean such a large increase in acidity?
    10·1 answer
  • What is the molarity of 20g of KNO, in 250 mL of water?
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!