answer.
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
yuradex [85]
2 years ago
6

Sodium is a soft metal with a relatively low work function. Light corresponding to 476 kJmol−1 was shone on the sodium metal, an

d the electrons detected had a velocity of 9.57×105ms−1. What is the work function of sodium metal based on this data? The mass of an electron is 9.11×10−31kg.
Chemistry
1 answer:
azamat2 years ago
4 0

Answer:

7.93 * 10^-19 J

Explanation:

Kinetic energy of the electrons = 1/2 mv^2

Hence;

KE = 1/2 * 9.11×10^−31 (9.57×10^5)^2

KE = 4.975 * 10^-23 J

Energy of incident light = 476 * 10^3/6 * 10^23 = 79.3 * 10^-20 J

From Einstein's photoelectric equation;

KE = E - W

Where;

KE = kinetic energy of ejected electron

E = energy of incident photon

W = Work function of the metal

Hence;

W = E - KE

W = 7.93 * 10^-19 - 4.975 * 10^-23

W = 7.93 * 10^-19 J

You might be interested in
A fox spots a rabbit in a field. The fox begins to chase the rabbit, and the rabbit runs away. Which statement best describes th
Ira Lisetskai [31]

Answer:

2 I Think

Explanation:

8 0
2 years ago
Read 2 more answers
What volume of 0.210 M sulfuric acid is required to completely react with 2.14 g aluminium hydroxide?
Galina-37 [17]
3 H2SO4 + 2 Al(OH)3 → Al2(SO4)3 + 6 H2O

(2.14 g Al(OH)3) / (78.0036 g Al(OH)3/mol) x (3 mol H2SO4 / 2 mol Al(OH)3) / (0.210 mol/L H2SO4) =
0.19596 L = 196 mL H2SO4
3 0
2 years ago
CuSO4(aq) + 2NaOH(aq) Cu(OH)2(s) + Na2SO4(aq)
REY [17]
Your answer is right.

Important elements to consider:

- to use the balanced equation (which you did)
- divide the masses of each compound by the correspondant molar masses (which you did)
- compare the theoretical proportions with the current proportions

Theoretical: 2 mol of Na OH : 1 mol of CuSO4
Then 4 mol of NaOH need 2 mol of CUSO4.

Given that you have more than 2 mol of of CUSO4 you have plenty of it and the NaOH will consume first, being this the limiting reagent.

6 0
2 years ago
A 0.529-g sample of gas occupies 125 ml at 60. cm of hg and 25°c. what is the molar mass of the gas?
Llana [10]

<span>Let's </span>assume that the gas has ideal gas behavior. <span>
Then we can use ideal gas formula,
PV = nRT<span>

</span><span>Where, P is the pressure of the gas (Pa), V is the volume of the gas (m³), n is the number of moles of gas (mol), R is the universal gas constant ( 8.314 J mol</span></span>⁻¹ K⁻¹) and T is temperature in Kelvin.<span>
<span>
</span>P = 60 cm Hg = 79993.4 Pa
V = </span>125  mL = 125 x 10⁻⁶ m³

n = ?

<span> R = 8.314 J mol</span>⁻¹ K⁻¹<span>
T = 25 °C = 298 K
<span>
By substitution,
</span></span>79993.4 Pa<span> x </span>125 x 10⁻⁶ m³ = n x 8.314 J mol⁻¹ K⁻¹ x 298 K<span>
                                          n = 4.0359 x 10</span>⁻³ mol

<span>
Hence, moles of the gas</span> = 4.0359 x 10⁻³ mol<span>

Moles = mass / molar mass

</span>Mass of the gas  = 0.529 g 

<span>Molar mass of the gas</span> = mass / number of moles<span>
                                    = </span>0.529 g / 4.0359 x 10⁻³ mol<span>
<span>                                    = </span>131.07 g mol</span>⁻¹<span>

Hence, the molar mass of the given gas is </span>131.07 g mol⁻¹

4 0
2 years ago
Water flowing at the rate of 13.85 kg/s is to be heated from 54.5 to 87.8°C in a heat exchanger by 54 to 430 kg/h of hot gas flo
weeeeeb [17]

Answer:

=> 572.83 K (299.83°C).

=> 95.86 m^2.

Explanation:

Parameters given are; Water flowing= 13.85 kg/s, temperature of water entering = 54.5°C and the temperature of water going out = 87.8°C, gas flow rate 54,430 kg/h(15.11 kg/s). Temperature of gas coming in = 427°C = 700K, specific heat capacity of hot gas and water = 1.005 kJ/ kg.K and 4.187 KJ/kg. K, overall heat transfer coefficient = Uo = 69.1 W/m^2.K.

Hence;

Mass of hot gas × specific heat capacity of hot gas × change in temperature = mass of water × specific heat capacity of water × change in temperature.

15.11 × 1.005(700K - x ) = 13.85 × 4.187(33.3).

If we solve for x, we will get the value of x to be;

x = 572.83 K (2.99.83°C).

x is the temperature of the exit gas that is 572.83 K(299.83°C).

(b). ∆T = 339.2 - 245.33/ln (339.2/245.33).

∆T = 93.87/ln 1.38.

∆T = 291.521K.

Heat transfer rate= 15.11 × 1.005 × 10^3 (700 - 572.83) = 1931146.394.

heat-transfer area = 1931146.394/69.1 × 291.521.

heat-transfer area= 95.86 m^2.

7 0
2 years ago
Other questions:
  • A 25.0 ml sample of an unknown hbr solution is titrated with 0.100 m naoh. the equivalence point is reached upon the addition of
    7·1 answer
  • Consider the two electron arrangements for neutral atoms A and B. What is the difference between atom A and atom B? A - 1s2, 2s2
    11·2 answers
  • a student adds 15 g of baking soda to 10 g of acetic acid in a beaker. a chemical reaction occurs and a gas is given off. after
    10·1 answer
  • How many carbon atoms are contained in 2.8 g of c2h4 ?
    13·2 answers
  • You are planning to prepare 600 mL of 20% dextrose solution, by mixing your 5% and 50% dextrose solution. How much of each solut
    12·1 answer
  • What is the empirical formula of a compound which contains 84.4% c and 15.6% h by mass?
    14·1 answer
  • Using your data above, draw conclusions about the d-splitting for each ligand (H2O, en, phen). Order the complexes from least to
    13·1 answer
  • Jared sprayed a pesticide on his garden three times. The first time, many insects died. The second time fewer insects died. The
    11·2 answers
  • Methane and chlorine react to form chloromethane, CH3Cl and hydrogen chloride. When 29.8 g of methane and 40.3 g of chlorine gas
    10·2 answers
  • Which of these is NOT true about the outer core? Question 4 options: It is mostly made up of iron and nickel. It is mostly liqui
    9·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!