Which of these compounds has the largest percentage by mass of nitrogen? NO N2O NO2 N2O3

How much energy is required to heat 2kg of ice from -5°c to 0°c

balu736 [363]

Explanation:

total heat = Heat required to convert 2 kg of ice to 2 kg of water at 0 °C + Heat required to convert 2 kg of water at 0 °C to 2 kg of water at 20 °C.

Heat=mhfg+mCpΔT

Here, m ( mass of ice) = 2 kg

hfg (latent heat of fusion of ice) = 334 KJ

Cp of water (specific heat) = 4.187 KJ/Kg-K

ΔT(Temperature difference) = 20 °C

Therefore, Heat required = 2 x 334 + 2 x 4.187 x (20 - 0 )

Heat reqd= 835.48 KJ

Therefore, to melt 2 kg of ice 835.48 KJ of heat is required.

4 0

2 years ago

A solid sample is hit with a hammer and breaks into jagged, irregular shards. What type of solid was it? A) molecular solid b) n

DaniilM [7]

I honestly don't know the answer

8 0

3 years ago

Which substance contains only 1 kind of atom

Nataliya [291]

Elements are substances that contain only 1 kind of atom.

8 0

3 years ago

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The chemical formula for sulfuric acid is H2SO4. In one molecule of sulfuric acid, there are _____.

erma4kov [3.2K]

Answer:

four atoms of oxygen

Explanation:

two atoms of hydrogen

one sulphur atom

5 0

3 years ago

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

RideAnS [48]

The kinetic energy of the emitted electrons of cesium when it is exposed to UV rays of frequency $1.0 \times {10^{15}}\;{\text{Hz}}$ is $\boxed{6.63 \times {{10}^{ - 19}}\;{\text{J}}}$

Further Explanation:

Photoelectric effect:

When light is made to fall on any substance, electrons are emitted from it. This is known as the photoelectric effect and the emitted electrons are called photoelectrons. The electrons are emitted because of the transference of energy from light to the electrons.

Cesium is a member of the alkali metal group so it is highly reactive and shows photoelectric effect to the maximum extent. It can remove its electron so easily because of its atomic size. Due to large atomic size of cesium, its outermost electrons are held very less tightly to the nucleus and therefore removed easily.

According to the Planck-Einstein equation, the energy is proportional to the frequency and is expressed as follows:

${\mathbf{E=h\nu }}$ ......(1)

Here,

${\text{E}}$ is the energy.

$h$ is the Plank’s constant.

$\nu$ is the frequency.

The frequency of UV rays is $1.0 \times {10^{15}}\;{\text{Hz}}$ or $1.0 \times {10^{15}}\;{{\text{s}}^{ - 1}}$

The value of Planck’s constant is $6.626 \times {10^{ - 34}}\;{\text{J}}\cdot{\text{s}}$ .

Substitute these values in equation (1)

$\begin{aligned}{\text{E}}&=\left( {6.626 \times {{10}^{ - 34}}\;{\text{J}}\cdot{\text{s}}}\right)\left( {1.0 \times {{10}^{15}}\;{{\text{s}}^{ - 1}}}\right)\\&=6.63\times {10^{ - 19}}\;{\text{J}}\\\end{aligned}$

But when electrons are ejected out from the surface of the substance, all of its energy is considered as kinetic energy.

So the kinetic energy of the electrons is ${\mathbf{6}}{\mathbf{.63 \times 1}}{{\mathbf{0}}^{{\mathbf{ - 19}}}}\;{\mathbf{J}}$ .

Learn more:

1. Statement about subatomic particle: brainly.com/question/3176193

2. The energy of a photon in light: brainly.com/question/7590814

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Structure of the atom

Keywords: kinetic energy, frequency, energy, photoelectric effect, Planck's constant, light, electrons, photoelectrons, proportional, transference, reactive, cesium.

7 0

3 years ago

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