calculate the number of photons having a wavelength of 10 waves/s required to produce 1.0 kJ of energy

When magnesium metal is heated in air it begins to release large amounts of heat and light. What kind of a reaction is this an e

Salsk061 [2.6K]

It is called exothermic reaction because it releases heat and light and it is called combustion reaction because it is reacting and is being oxidised by O2 to MgO. It can also be called as oxidation reaction since Mg is oxidised to MgO.

5 0

3 years ago

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Which of the following isoelectronic series is correctly ranked from largest ionic radius to smallest ionic radius? 1. N 3−, O 2

love history [14]

Answer:

Option 1: N⁻³ > O⁻² > F⁻ > Na⁺ > Mg⁺²

Explanation:

Ionic radius is the radius of an atom´s ion in ionic crystal structure. In an ion that lose an electron, to form a cation, the radius of the ion gets smaller, because the repulsion between electrons decrease because fewer electrons are present. Conversely, adding on electron to a neutral atom, to form an anion, causes electron - electron repulsions to increase, so the size of the radius of the ion gets bigger.

Isoelectronic species are ions or elements that have the same number of electrons in their electronic shells but have different overall charges, because of their different atomic numbers.

In a isolelectronic series (same number of electrons), the increase of the positive charge (given by the number of protons in the nucleus), will cause a decrease in radius beacuse the greater electrostatic attraction between the electrons and the nucleus. Consequently, the ion with the greatest nuclear charge will have the smallest ionic radius and the ion with the smallest nulear charge will have the largest ionic radius.

We will use this principle to solve our problem.

In our case, the given ions are:

N⁻³ : Z = 7, e⁻ = 10
O⁻²: Z= 8, e⁻ =10
F⁻: Z = 9, e⁻ = 10
Na⁺: Z= 11, e⁻ = 10
Mg⁺²: Z=12, e⁻ =10

where Z= number of protons, and e⁻ = number of electrons.

Hence the decreasing order of ionic radius is:

N⁻³ > O⁻² > F⁻ > Na⁺ > Mg⁺²

Have a nice day!

4 0

3 years ago

An unknown noble gas has a density of 5.84 g dm-3 at STP. Calculate its molar mass, and so identify the gas.

bagirrra123 [75]

The noble gas is Xenon and its molar mass is 131 g/mol.

<h3>What is the molar mass of the noble gas?</h3>

The molar mass of the noble gas is determined as follows;

Let molar mass of unknown gas be M, and mass of gas be m

Density of the noble gas, ρ = 5.8 g/dm³

density = m/V

At STP;

temperature, T = 273.15 K
pressure, P = 1 atm
molar gas constant, R = 0.0821 L.atmK⁻¹mol⁻¹

From ideal gas equation:

PV = nRT

where n = m/M

PV = mRT/M

M = mRT/PV

M = 0.0821 * 273.15 * 5.84/1

Molar mass of the noble gas = 131 g/mol

The noble gas is Xenon which has molar mass approximately equal to 131 g/mol.

Learn more about molar mass at: brainly.com/question/837939

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6 0

1 year ago

Which method would you use to separate rice grains, which have accidentally been mixed with flour

ale4655 [162]

Answer:

I would sieve them because the flour will go through but not the rice

Explanation:

6 0

2 years ago

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The terms Q and K refer to reaction components at non-equilibrium and equilibrium conditions, respectively. For a forward reacti

daser333 [38]

Answer:

The value of Q must be less than that of K.

Explanation:

The difference of K and Q can be understood with the help of an example as follows

A ⇄ B

In this reaction A is converted into B but after some A is converted , forward reaction stops At this point , let equilibrium concentration of B be [B] and let equilibrium concentration of A be [A]

In this case ratio of [B] and [A] that is

K = [B] / [A] which is called equilibrium constant.

But if we measure the concentration of A and B ,before equilibrium is reached , then the ratio of the concentration of A and B will be called Q. As reaction continues concentration of A increases and concentration of B decreases. Hence Q tends to be equal to K.

Q = [B] / [A] . It is clear that Q < K before equilibrium.

If Q < K , reaction will proceed towards equilibrium or forward reaction will

proceed .

8 0

3 years ago

calculate the number of photons having a wavelength of 10 waves/s required to produce 1.0 kJ of energy​

calculate the number of photons having a wavelength of 10 waves/s required to produce 1.0 kJ of energy