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3 years ago

Hoon2. In words, describe how the changing positions of the sun, moon, and Earthleadthe different moon phases.

Chemistry

1 answer:

zysi [14]3 years ago

7 0

As the Sun sets, the moon rises with the tide that faces the Earth fully exposed to sunlight. The moon has phases because of its orbit to Earth which causes the portion we see illuminated to change. The new moon occurs when the moon is positioned between the earth and the sun. at full moon and third quarter or called as the half moon, it happens when the moon is at a 90 degree angle with respect to the earth and the sun. crescent refers to the moon that is less than half illuminated by the sun. gibbous refers to more than half illuminated by the sun. waxing means growing or expanding in illumination and waning means shrinking or decreasing in illumination.

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What is responsible for the whistling sound that often accompanies firework?

Naya [18.7K]

The wistle is coming from all the chemicals including the fire you use to light the firework and a chemcial reaction is occuring which is the sound that is made because of this

8 0

3 years ago

1 point

monitta

Answer: C) a redox reaction that produces an electric current

Explanation:

Chemical cell is a device which is used for the conversion of the chemical energy produced in a redox reaction into the electrical energy. The cell consists of the negative terminal called as anode where oxidation takes place and a positive terminal called as cathode where reduction takes place.

Electrolytic cell is a device which is used to carry out chemical reactions by the use of electrical energy. The cell consists of the negative terminal called as cathode where reduction takes place and a positive terminal called as anode where oxidation takes place.

7 0

3 years ago

A sample of argon gas has a volume of 795 mL at a pres-sure of 1.20 atm and a temperature of 116 ∘C. What is the final volume of

jek_recluse [69]

Answer: The volume when the pressure and temperature has changed is $1.6\times 10^2mL$

Explanation:

To calculate the volume when temperature and pressure has changed, we use the equation given by combined gas law.

The equation follows:

$\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}$

where,

$P_1,V_1\text{ and }T_1$ are the initial pressure, volume and temperature of the gas

$P_2,V_2\text{ and }T_2$ are the final pressure, volume and temperature of the gas

Let us assume:

$P_1=1.20atm\\V_1=795mL\\T_1=116^oC=[116+273]K=389K\\P_2=0.55atm\\V_2=?mL\\T_2=75^oC=[75+273]K=348K$

Putting values in above equation, we get:

$\frac{1.20atm\times 795mL}{389K}=\frac{0.55atm\times V_2}{348K}\\\\V_2=\frac{1.20\times 795\times 348}{0.55\times 389}=1.6\times 10^3mL$

Hence, the volume when the pressure and temperature has changed is $1.6\times 10^2mL$

5 0

3 years ago

Q Q 3. (08.02 MC)

AnnyKZ [126]

Answer: A volume of 455 mL from 0.550 M KBr solution can be made from 100.0 mL of 2.50 M KBr.

Explanation:

Given: $V_{1}$ = ?, $M_{1}$ = 0.55 M

$V_{2}$ = 100.0 mL, $M_{2}$ = 2.50 M

Formula used to calculate the volume of KBr is as follows.

$M_{1}V_{1} = M_{2}V_{2}$

Substitute the values into above formula as follows.

$M_{1}V_{1} = M_{2}V_{2}\\0.55 M \times V_{1} = 2.50 M \times 100.0 mL\\V_{1} = 455 mL$

Thus, we can conclude that a volume of 455 mL from 0.550 M KBr solution can be made from 100.0 mL of 2.50 M KBr.

7 0

3 years ago

Read 2 more answers

Iron(III) oxide and hydrogen react to form iron and water, like this: Fe_2O_3(s) + 3H_2(g) rightarrow 2Fe(s) + 3H_2O(g) At a cer

Sergeeva-Olga [200]

Complete Question

The complete question is shown on the first uploaded image

Answer:

The equilibrium constant is $K_c= 2.8*10^{-4}$

Explanation:

From the question we are told that

The chemical reaction equation is

$Fe_{2} O_{3}_{(s)} + 3H_{2}_{(g)} -----> 2Fe_{(s)} + 3H_{2} O_{(g)}$

The voume of the misture is $V_m = 5.4L$

The molar mass of $Fe_{2} O_{3}_{(s)}$ is a constant with value of $M_{Fe_{2} O_{3}_{(s)} } = 160g/mol$

The molar mass of $H_{2}_{(g)}$ is a constant with value of $H_2 = 2g/mol$

The molar mass of $H_{2}O$ is a constant with value of $H_2O = 18g/mol$

Generally the number of moles is mathematically given as

$No \ of \ moles \ = \frac{mass}{molar\ mass}$

For $Fe_{2} O_{3}_{(s)}$

$No \ of\ moles = \frac{3.54}{160}$

$= 0.022125 \ mols$

For $H_{2}$

$No \ of\ moles = \frac{3.63}{2}$

$= 1.815 \ mols$

For $H_{2}O$

$No \ of\ moles = \frac{2.13}{18}$

$= 0.12 \ mols$

Generally the concentration of a compound is mathematicallyrepresented as

$Concentration = \frac{No \ of \ moles }{Volume }$

For $Fe_{2} O_{3}_{(s)}$

$Concentration[Fe_2 O_3] = \frac{0.222125}{5.4}$

$= 4.10*10^{-3}M$

For $H_{2}$

$Concentration[H_2] = \frac{1.815}{5.4}$

$= 0.336M$

For $H_{2}O$

$Concentration [H_2O] = \frac{0.12}{5.4}$

$= 0.022M$

The equilibrium constant is mathematically represented as

$K_c = \frac{[concentration \ of \ product]}{[concentration \ of \ reactant ]}$

Considering $H_2O \ for \ product$

And $H_2 \ for \ reactant$

At equilibrium the

$K_c = \frac{0.022}{0.336}$

$K_c= 2.8*10^{-4}$

3 0

3 years ago