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
Taya2010 [7]
3 years ago
11

When 16.9 g KOH is dissolved in 90.8 g of water in a coffee-cup calorimeter, the temperature rises from 18.5 °C to 34.27 °C. Wha

t is the enthalpy change per gram (in J/g) of KOH dissolved in the water? Assume that the solution has a specific heat capacity of 4.18 J/g×K. Water has a density of 1.00 g/ml. Be sure to enter the correct sign (+/-). Enter to 1 decimal place.
Chemistry
1 answer:
juin [17]3 years ago
4 0

Answer:

-431.5 J/g

Explanation:

Mass of solution = Mass of solute + mass of solvent

Solute is KOH while solvent is water.

Mass of KOH = 16.9 g

Mass of water = 90.8 g

Mass of solution = 16.9 + 90.8

                          = 107.7 g

Change in temperature (Δt) = 34.27 - 18.5

                                           = 16.2 °C

Heat required to raise the temperature of water is released by dissolving KOH.

Therefore,

Heat released by KOH = m × s× Δt

                                    = 107.7 × 4.18 × 16.2

                                    = 7293 J

Heat released by per g KOH = 7293 J/16.9 g

                                             = 431.5 J/g

As heat is released therefore, enthalpy change would be negative.

Enthalpy change of KOH = -431.5 J/g

You might be interested in
Determine the bonding type for boron trihydride given the electronegativity on the Pauling scale for boron is 2.0 and for hydrog
Anika [276]

Answer: The bond between boron and hydrogen in boron trihydride is covalent bond.

Explanation:

The type of bonding between the atoms forming a compound is determined by using the electronegativity difference between the atoms. According to the pauling's electronegativity rule:

  • If \Delta \chi=0, then the bond is non-polar.
  • If \Delta \chi\leq 1.7, then the bond will be covalent.
  • If \Delta \chi>1.7, then the bond will be ionic.

We are given:

Electronegativity for boron = 2.0

Electronegativity for hydrogen = 2.1

\Delta \chi=\chi_{H}-\chi_{B}\\\\\Delta \chi=2.1-2.0=0.1

As, \Delta \chi is less than 1.7 and not equal to 0. Hence, the bond between boron and hydrogen is covalent bond.

3 0
3 years ago
Please help......A 0.01 g bullet travels with a velocity of 1500 m/s. What is its momentum?
elena-s [515]

Answer:

hope this helps you

Explanation:

Example 1: A 20 kg object has a velocity of 4.5 m/s in the positive x direction. ... What is the momentum of a 3000 kg truck traveling at 25 m/s? 2. A 1500 kg ferryboat has a momentum of 25000 kg∙m/s. ... *A 0.01 kg bullet has a speed of 700 m/s before it strikes a 0.95 kg wooden block ... We will be going outside so please.

4 0
3 years ago
What mass of cu(s)cu(s) is electroplated by running 14. 5 aa of current through a cu2 (aq)cu2 (aq) solution for 4. 00 hh?
galina1969 [7]

The mass of Copper electroplated is 68.76 g

<h3>What is electroplating?</h3>

The process of plating a metal onto another is known as electroplating.

It is often used to prevent corrosion of metal or for the decorative purposes

In this process, electric current is passed through an aqueous solution containing dissolved cations.

The dissolved cations are reduced developing a thin metal coating on the electrode.

At cathode,

Cu^{2+}(aq) + 2e^-\rightarrow      Cu(s)

Current, I = 14.5 A

Time, t = 4 hrs = 4×60×60 = 14400 sec

Charge, q = It = 14.5×14400= 208800 C

Copper metal deposited by 2×96487 C = 63.55 g

Copper metal deposited by 208800 C = \frac{63.55 \times208800}{2\times96487}

                                                         = 68.76g

Hence, The mass of Copper electroplated is 68.76 g

Learn more about electroplating:

brainly.com/question/22104403

#SPJ4

4 0
1 year ago
Read 2 more answers
___1___Zn + __2___HCl → ___1___H2 + ____1__ZnCl2
strojnjashka [21]

Answer:

Mass = 2.8 g

Explanation:

Given data:

Mass of HCl = 102 g

Mass of Zn = 128 g

Mass of H₂ = ?

Solution:

Chemical equation:

2HCl + Zn      →     H₂ + ZnCl₂

Number of moles of Zn:

Number of moles = mass/molar mass

Number of moles = 128 g/ 65.38 g/mol

Number of moles = 2 mol

Number of moles of HCl:

Number of moles = mass/molar mass

Number of moles = 102 g/ 36.5 g/mol

Number of moles = 2.8  mol

Now we will compare the moles of hydrogen gas with HCl and Zn.

                   HCl          :        H₂

                     2            :        1

                     2.8         :       1/2×2.8 = 1.4 mol

                   Zn          :        H₂

                     1            :        1

                     2           :         2

Number of moles of hydrogen formed by HCl are less thus it will limiting reactant.

Mass of Hydrogen:

Mass = number of moles × molar mass

Mass = 1.4 mol ×  2 g/mol

Mass = 2.8 g

7 0
3 years ago
Answer:
Vlada [557]

Answer:Number of proton present in the nucleus of an atom of sulfur is 16.

Explanation:

Protons, neutrons and electrons are subatomic particles of an atom.

Atomic number of an atom is equal to the total number of protons present in the nucleus of an atom.

Z = total number of protons

Atomic mass of an atom is defined as sum of the number of protons and neutrons present in the nucleus of an atom.

In neutral atom there are equal number of protons and electron.

A = number of proton + number of neutrons

According to question, there are 16 electrons in neutral atom of Sulfur.

in a neutral atom:

Number of electrons = Number of protons = 16

Number of proton present in the nucleus of an atom of sulfur is 16.

7 0
3 years ago
Other questions:
  • What is a functional group?
    7·2 answers
  • What is the name of the movement of the Earth around the Sun as pointed out by letter J.
    10·1 answer
  • If a solution were to change its composition during freezing, how do you think this would change the cooling curve?
    9·1 answer
  • You want to create a garden that is 9 km long, 8.35 hm wide, and 35 cm deep. Calculate the volume in m^3 of dirt that you will n
    12·1 answer
  • Under the same conditions of temperature and pressure, which of the following gases would behave most like an ideal gas? A)He(g)
    14·1 answer
  • If the rate of reaction of [0.1 M] sodium cyanide with [0.1 M] 2-bromo-2-methylpropane is 1.2 x 10-3 M/s, what would be the effe
    11·1 answer
  • If the vapor pressure of pure benzene is 96.1 mm Hg, what must the vapor pressure of pure toluene be in order for the 50/50 % mi
    7·1 answer
  • Given the following isotopes of strontium, calculate the average atomic mass.
    11·1 answer
  • Which property is NOT used to separate a mixture?
    6·1 answer
  • When an atom becomes charged what is transferred?
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!