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4 years ago

What is the kinetic energy of the emitted electrons when cesium is exposed to UV rays of frequency 1.0×1015Hz?

1 answer:

3 0

In order to emit electrons, the cesium will have to absorb photons. Each photon will knock out one electron by transferring its energy to the electron. Therefore, by the principle of energy conservation, the energy of the removed electron will be equal to the energy of the incident photon. That energy is calculated using Planck's equation:

E = hf

E = 6.63 x 10⁻³⁴ * 1 x 10¹⁵
E = 6.63 x 10⁻¹⁹ Joules

The electron will have 6.63 x 10⁻¹⁹ Joules of kinetic energy

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Which of the following elements are already balanced in this equation? FeS₂ + Cl₂ → FeCl₃ + S₂ Cl₂

Anuta_ua [19.1K]

Fe and S are already balanced in this equation

<h3>Further explanation</h3>

Balanced indicates that the number of elements in question has the same number of atoms both on the left side (the number on the reactants side) and on the right side (the number on the product side)

Even though one of the elements is said to be balanced, the chemical equation as a whole cannot be said to be balanced, because the chemical equation has several components of the constituent elements.

To balance chemical equations, a coefficient in front of the compound is usually added either in the reactants or products

Reaction

FeS₂ + Cl₂ → FeCl₃ + S₂Cl₂

From this equation, it can be shown that: the Fe and S elements are balanced because the numbers are equal both on the left and right, while the Cl elements are not yet balanced

Fe, left=1, right=1 ⇒ balanced

S, left=2, right=1 ⇒ balanced

Cl, left=2, right=5⇒ not balanced

For balanced equations:

2FeS₂ + 5Cl₂ → 2FeCl₃ + 2S₂Cl₂

8 0

3 years ago

Helium (he) has two valence electrons, and these electrons are located in the 1s subshell. Without using the periodic table, in

Serggg [28]

helium is in group 8 and period 1

5 0

3 years ago

2.50g of a certain Compound X, known to be made of carbon, hydrogen and perhaps oxygen, and to have a molecular molar mass of 12

Art [367]

Answer:

Molecular Formula = C₁₀H₈

Explanation:

Step 1: <u>Calculating Moles for each Element:</u>

C = Mass of CO₂ × (1 mol of CO₂÷ M.Mass of CO₂) × (1 mol of C ÷ 1 mol of CO₂)

C = 8.60 g × (1 mol of CO₂÷ 44.011 g.mol⁻¹) × (1 mol of C ÷ 1 mol of CO₂)

C = 0.1954 mol

H = Mass of H₂O × (1 mol of H₂O ÷ M.Mass of H₂O) × (2 mol of H ÷ 1 mol of H₂O)

H = 1.41 g × (1 mol of H₂O ÷ 18.106 g.mol⁻¹) × (2 mol of H ÷ 1 mol of H₂O)

H = 0.1557 mol

Step 2: <u>Calculate the Smallest whole number ratio as,</u>

C H

0.1954 0.1557

0.1954/0.1557 0.1557/0.1557

1.25 1

Multiply ratio by 4,

5 4

Result:

Empirical Formula of Propane is C₅H₄

Step 3: <u>Calculate Molecular Formula:</u>

Molecular formula is calculated by using following formula,

Molecular Formula = n × Empirical Formula ---- (1)

Also, n is given as,

n = Molecular Weight / Empirical Formula Weight

Molecular Weight = 128.0 g.mol⁻¹

Empirical Formula Weight = 5 (C) + 4 (H) = 64 g.mol⁻¹

So,

n = 128.0 g.mol⁻¹ ÷ 64 g.mol⁻¹

n = 2

Putting Empirical Formula and value of "n" in equation 1,

Molecular Formula = 2 × C₅H₄

Molecular Formula = C₁₀H₈

4 0

3 years ago

How can water and gravity work together to erode soil,sediment,and rock

Sunny_sXe [5.5K]

Ever seen a waterfall ? what do you think happens when all that water slams into the ground below ? same as when you turn a hosepipe on a flowerbed.

also, there's hydraulic cracking where water gets into cracks and freezes, splitting rocks apart.

fast moving water can carry sediment and roll rocks along the bottom. if the water slows down, it drops the rocks and heavier sediment. if it floods a field, say, then drains away, the grass will also filter smaller particles out, or the water might evaporate and leave fine sediment behind.

6 0

4 years ago

Read 2 more answers

Based on your observations from the glowing splint test with oxygen gas, briefly explain why liquid oxygen is a very hazardous s

Cerrena [4.2K]

Answer:

liquid oxygen is highly flammable

Explanation:

near any source of heat. liquid oxygen can explode to flames thus being hazardous

3 0

3 years ago