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3 years ago

Suppose you have a container filled with iron and sand. You can separate the iron from the sand if you ____________ so this is a

Chemistry

1 answer:

irinina [24]3 years ago

4 0

Answer:

Use a magnet; Mixture

Explanation:

Suppose you have a container filled with iron and sand. You can separate the iron from the sand if you use a magnet so this is a mixture.

A mixture is made up of two more components that are not chemically combined.
Mixtures may be classified as homogeneous when the components are in the same phase or heterogeneous when the components are in different phases.
A mixture of sand and iron is an example of solid-solid mixture which can be separated using a magnet.
The magnet will attract the iron in the mixture leaving the sand.

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The equation for photon energy, E , is

Sidana [21]

The wavelength of a photon that has an energy of E = 3.69×10−19 J is 5.42 x 10⁻⁷ m.

<h3>What do you mean by wavelength?</h3>

The space between corresponding points (adjacent crests) in adjacent cycles is known as the wavelength () of a waveform signal that is sent in space or down a wire.

The wavelength can be calculated by the given formula

E = hc/λ

Where, E is energy = 3.65 x 10⁻¹⁹ J

h is plank's constant = 6.626 x 10⁻³⁴ J.sec

c is speed of light = 2.9 × 10⁸ m/s

Putting the values in the formula

λ = (6.626 x 10⁻³⁴)(2.9 × 10⁸) / (3.65 x 10⁻¹⁹) = 5.42 x 10⁻⁷ m.

Thus, the wavelength, λ is 5.42 x 10⁻⁷ m.

Learn more about wavelength

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4 0

2 years ago

Instant cold packs, often used to ice athletic injuries on the field, contain ammonium nitrate and water separated by a thin pla

RSB [31]

<u>Answer:</u> The enthalpy change of the reaction is -27. kJ/mol

<u>Explanation:</u>

To calculate the mass of water, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Density of water = 1 g/mL

Volume of water = 25.0 mL

Putting values in above equation, we get:

$1g/mL=\frac{\text{Mass of water}}{25.0mL}\\\\\text{Mass of water}=(1g/mL\times 25.0mL)=25g$

To calculate the heat released by the reaction, we use the equation:

$q=mc\Delta T$

where,

q = heat released

m = Total mass = [1.25 + 25] = 26.25 g

c = heat capacity of water = 4.18 J/g°C

$\Delta T$ = change in temperature = $T_2-T_1=(21.9-25.8)^oC=-3.9^oC$

Putting values in above equation, we get:

$q=26.25g\tiimes 4.18J/g^oC\times (-3.9^oC)=-427.9J=-0.428kJ$

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

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

Given mass of ammonium nitrate = 1.25 g

Molar mass of ammonium nitrate = 80 g/mol

Putting values in above equation, we get:

$\text{Moles of ammonium nitrate}=\frac{1.25g}{80g/mol}=0.0156mol$

To calculate the enthalpy change of the reaction, we use the equation:

$\Delta H_{rxn}=\frac{q}{n}$

where,

q = amount of heat released = -0.428 kJ

n = number of moles = 0.0156 moles

$\Delta H_{rxn}$ = enthalpy change of the reaction

Putting values in above equation, we get:

$\Delta H_{rxn}=\frac{-0.428kJ}{0.0156mol}=-27.44kJ/mol$

Hence, the enthalpy change of the reaction is -27. kJ/mol

4 0

3 years ago

Helooo i need help please :)

Tatiana [17]

It is a ,d and c just make sure tho

6 0

3 years ago

Why does electronegativity increase as you move from left to right across

Katen [24]

Answer: increasing number of protons increases the positive charge of the nucleus.

Explanation: because as the electronegativity moves from left to right on the periodic table the protons do increase to make it into a positive charge.

7 0

3 years ago

What is the pH of a solution of 0.800 M KH2PO4, potassium dihydrogen phosphate?

Nookie1986 [14]

KH₂PO₄ hydrolyzes as;
H₂PO₄⁻ + H₂O ↔ H₃PO₄ + OH⁻
Let x amount of H₂PO₄⁻ has reacted with water then,
Kb₁ = [H₃PO₄][OH⁻] / [H₂PO₄⁻]
[H₂PO₄⁻] = 0.8-x M
Kb₁ = x² / (0.8 - x)
Given Ka₁ = 7.5 x 10⁻³
so Kb₁ = 1 x 10⁻¹⁴ / (7.5 x 10⁻³) = 1.33 x 10⁻¹²
From this information:
1.33 x 10⁻¹² = x² / 0.8
x = [OH⁻] = 1.03 x 10⁻⁶ M
pOH = - log (1.03 x 10⁻⁶) = 5.99
pH = 14 - pOH = 14 - 5.99 = 8.01

3 0

3 years ago