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3 years ago

What is the Energy of a wave whose frequency is 8.45 x 10^14 Hz?

Chemistry

1 answer:

allsm [11]3 years ago

8 0

Answer:

E = hf

E = hc/lamda

where E-energy,

h-planck's constant (6.62 x 10^-34 Js)

f- frequency ( f = c/lamda)

c-velocity of light ( 3 x 10^8 m/s)

lamda- wavelength

you can this formula to solve all the 4 questions.

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Which is the anode and which is the cathode?

rewona [7]

Answer:

2l- ---> l2 + 2e- is the anode

2H+ + 2e- ---> H2(g) is the cathode

Explanation:

Oxidation occurs when a metal loses two or more electrons in a redox chemical reaction and reduction is when it gains. Thus, oxidation is the anode and reduction is the cathode.

5 0

3 years ago

PLEASE HELP ME ASAPPPPP What is the density of a piece of cardboard that has a mass of 250 g and volume of 46 mL? *

Roman55 [17]

Answer:

The answer is

Explanation:

The density of a substance can be found by using the formula

$density = \frac{mass}{volume} \\$

From the question

mass = 250 g

volume = 46 mL

The density is

$density = \frac{250}{46} \\ = 5.4347826...$

We have the final answer as

Hope this helps you

6 0

3 years ago

2. The reaction of zinc with nitric acid was carried out in a calorimeter. This reaction caused the temperature

snow_lady [41]

We want to solve Q = mcΔT for the liquid water; its change in temperature will tell us the amount of thermal energy that flowed out of the reaction. The specific heat, c, of water is 4.184 J/g °C.

Q = (72.0 g)(4.184 J/g °C)(100 °C - 25 °C) = 22593.6 J

Q ≈ 2.26 × 10⁴ J or 22.6 kJ (three significant figures).

3 0

3 years ago

Problem PageQuestion Sulfuric acid is essential to dozens of important industries from steelmaking to plastics and pharmaceutica

Feliz [49]

The question is incomplete, here is the complete question:

Sulfuric acid is essential to dozens of important industries from steel making to plastics and pharmaceuticals. More sulfuric acid is made than any other industrial chemical, and world production exceeds 2.0×10¹¹ kg per year.

The first step in the synthesis of sulfuric acid is usually burning solid sulfur to make sulfur dioxide gas. Suppose an engineer studying this reaction introduces 1.8 kg of solid sulfur and 10.0 atm of oxygen gas at 650°C into an evacuated 50.0 L tank. The engineer believes Kp = 0.099 for the reaction at this temperature.

Calculate the mass of solid sulfur he expects to be consumed when the reaction reaches equilibrium. Round your answer to 2 significant digits.

<u>Answer:</u> The mass of solid sulfur that will be consumed is 19. grams

<u>Explanation:</u>

The chemical equation for the formation of sulfur dioxide gas follows:

$S(s)+O_2\rightarrow SO_2(g)$

<u>Initial:</u> 10.0

<u>At eqllm:</u> 10-x x

The expression of $K_p$ for above equation follows:

$K_p=\frac{p_{SO_2}}{p_{O_2}}$

We are given:

$K_p=0.099$

Putting values in above expression, we get:

$0.099=\frac{x}{10-x}\\\\x=0.901atm$

Partial pressure of sulfur dioxide = x = 0.901 atm

To calculate the number of moles, we use the equation given by ideal gas which follows:

$PV=nRT$

where,

P = pressure of the sulfur dioxide gas = 0.901 atm

V = Volume of the gas = 50.0 L

T = Temperature of the gas = $650^oC=[650+273]K=923K$

R = Gas constant = $0.0821\text{ L. atm }mol^{-1}K^{-1}$

n = number of moles of sulfur dioxide gas = ?

Putting values in above equation, we get:

$0.901atm\times 50.0L=n\times 0.0821\text{ L. atm}mol^{-1}K^{-1}\times 923K\\\\n=\frac{0.901\times 50.0}{0.0821\times 923}=0.594mol$

By stoichiometry of the reaction:

1 mole of sulfur dioxide gas is produced from 1 mole of sulfur

So, 0.594 moles of sulfur dioxide gas will be produced from = $\frac{1}{1}\times 0.594=0.594mol$ of sulfur

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Moles of sulfur = 0.594 moles

Molar mass of sulfur = 32 g/mol

Putting values in above equation, we get:

$0.594mol=\frac{\text{Mass of sulfur}}{32g/mol}\\\\\text{Mass of sulfur}=(0.594mol\times 32g/mol)=19.008g$

Hence, the mass of solid sulfur that will be consumed is 19. grams

8 0

3 years ago

What does the t cell do to your body?

lawyer [7]

Answer: it's part of the immune system that focuses on specific foreign particles. Rather than generically attack any antigens, T cells circulate until they encounter their specific antigen. As such, T cells play a critical part in immunity to foreign substances !

Explanation:

4 0

3 years ago