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3 years ago

What is the frequency of light that has an energy of 1.8 x 10-15 J? 6.626 x 10-34 Js 2.7 x 1018 Hz 3.7 x 10-19 Hz 1.2 x 10-48 Hz

1 answer:

8 0

In order to determine the frequency, we may use Planck's equation:

Energy = Planck's constant * frequency

Rearranging and substituting the values,

frequency = (1.8 x 10⁻¹⁵) / (6.63 x 10⁻³⁴)
f = 2.71 x 10¹⁸ Hz

The frequency of the light is 2.7 x 10¹⁸ Hz

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Which of the following statements regarding radiation are FALSE?

kari74 [83]

Answer:

All of the given statements are true.

Explanation:

All the elements are heavier than Bismuth (Bi) are radioactive.

The time for half of the original sample to spontaneous decay is called half life ( $t_{1/2}$ )

$t_{1/2}=\frac{ln\:2}{\lambda}\\\lambda\:is\:the\:radioactive\:decay\:constant$

All radioactive elements are spontaneously decaying towards formation of a stable element.

Radioactive elements undergo decay in order to attain stability.

Radioactivity is a natural part of our environment. The earth also contains several primordial long-lived radioisotopes that have survived to the present in significant amounts.

Hence, all the given statements are true.

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3 years ago

Determine the energy change in the following reaction. This reaction is considered ...

Juliette [100K]

Answer:isothermic

Explanation:

8 0

3 years ago

Read 2 more answers

Ideal He gas expanded at constant pressure of 3 atm until its volume was increased from 9 liters to 15 liters. During this proce

kkurt [141]

Explanation:

The given data is as follows.

P = 3 atm

= $3 atm \times \frac{1.01325 \times 10^{5} Pa}{1 atm}$

= $3.03975 \times 10^{5} Pa$

$V_{1}$ = 9 L = $9 \times 10^{-3} m^{3}$ (as 1 L = 0.001 $m^{3}$ ),

$V_{2}$ = 15 L = $15 \times 10^{-3} m^{3}$

Heat energy = 800 J

As relation between work, pressure and change in volume is as follows.

W = $P \times \Delta V$

or, W = $P \times (V_{2} - V_{1})$

Therefore, putting the given values into the above formula as follows.

W = $P \times (V_{2} - V_{1})$

= $3.03975 \times 10^{5} Pa \times (15 \times 10^{-3} m^{3} - 9 \times 10^{-3} m^{3})$

= 1823.85 Nm

or, = 1823.85 J

As internal energy of the gas $\Delta E$ is as follows.

$\Delta E$ = Q - W

= 800 J - 1823.85 J

= -1023.85 J

Thus, we can conclude that the internal energy change of the given gas is -1023.85 J.

8 0

3 years ago

Using the reaction below: 2 CO2(g) + 2 H2O(l) → C2H4(g) + 3 O2(g) ΔHrxn= +1411.1 kJ What would be the heat of reaction for this

maw [93]

Answer: d) -705.55 kJ

Explanation:

Heat of reaction is the change of enthalpy during a chemical reaction with all substances in their standard states.

$2CO_2(g)+2H_2O(l)\rightarrow C_2H_4(g)+3O_2(g)$ $\Delta H=+1411.1kJ$

Reversing the reaction, changes the sign of $\Delta H$

$C_2H_4(g)+3O_2(g)\rightarrow 2CO_2(g)+2H_2O(l)$

$\Delta H=-1411.1kJ$

On multiplying the reaction by $\frac{1}{2}$ , enthalpy gets half:

$0.5C_2H_4(g)+1.5O_2(g)\rightarrow CO_2(g)+H_2O(l)$ $\Delta H=\frac{1}{2}\times -1411.1kJ=-705.55kJ/mol$

Thus the enthalpy change for the given reaction is -705.55kJ

7 0

3 years ago

The thermite reaction reacts iron (III) oxide, Fe2O3, with aluminium powder,Al, the form aluminium oxide, Al2O3 and iron, Fe.

lara [203]

Answer:

This answer assumes that the strated "16.0g of iron" was meant to be 16.0 grams of iron(III) oxide.

Explanation:

To start, the thermite equation must be balanced.

I find:

1Fe2O3 + 2Al = 1Al2O3 + 2Fe

This tells us we need 2 moles of Al for every 1 mole of Fe2O3.

Now calculate the moles of each reactant:

Moles Fe2O3: 16.0 g/159.7 g/mole = 0.100 moles Fe2O3

Moles Al: 8.1 /26.98 g/mole = 0.300 moles Al

The balanced equation says that in order to react all of the Fe2O3 we'd need twice that amount (in moles) of the Al. (0.100 moles Fe2O3)*(2) = 0.200 moles Al.

Which of the two reactants is the limiting reagent?

We have more than enough moles of Al to react with 0.10 moles of Fe2O3. (We have 0.300 moles Al and all we need is 0.200 moles to react with the 0.10 moles of Fe2O3. Fe2O3 is the limiting reagent.

Calculate the maximum mass of iron of iron that could be formed using these quantities of reactants.

The balanced equation tells us that we will obtain 2 moles of Fe for every 1 mole of Fe2O3 consumed. Since Fe2O3 is the limiting reagent, we will assume that it completely reacts. That means 0.1 moles of Fe2O3 is reacted. Since we expect twice that many moles of Fe, we should obtain 0.200 moles of Fe. At 55.85 g/mole, we should obtain:

(0.200 moles Fe)*(55.85 g Fe/mole Fe) = 11.2 grams Fe

5 0

2 years ago