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4 years ago

Which equation explains where the energy that is released from stars comes from?

2 answers:

8 0

Even though this is the wrong subject (it belongs in phycis section, not chemistry), the answer would be E=mc^2. This equation gives the amount of nuclear energy contained in a certain mass of matter, and stars use nuclear reactions to release energy.

il63 [147K]4 years ago

6 0

Answer:

D. $E=m\ c^2$

Explanation:

Star is huge glowing hot gas ball which mainly consists of hydrogen and helium.

The energy source of the stars are the nuclear fission and the fusion reaction taking place within the stars.

The energy of such reactions is calculated by using the Einstein's equation as:-

$Energy=m\times c^2$

Thus, the correct answer is:- D. $E=m\ c^2$

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Use the drop-down menus to identify each organic reaction as an addition, substitution, elimination, or condensation reaction. (

Bezzdna [24]

A chemical reaction involves an interaction between two or more species to yield a product.

<h3>What is a chemical reaction?</h3>

A chemical reaction involves an interaction between two or more species to yield a product.

The following is the classification of the reactions based on type;

The first reaction shown in the attachment is a condensation reaction
The second reaction is an addition reaction
The third reaction is an elimination reaction
The fourth reaction is a substitution reaction

Learn more about reaction:brainly.com/question/9524025

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3 0

3 years ago

(?)Na2HPO4 → (?)Na4P2O7 + (?)H2O

Akimi4 [234]

Answer: 2,1,1

Explanation: (2)Na2HPO4=(1)Na4P2O7+(1)H20

7 0

4 years ago

Determine the empirical and molecular formula for chrysotile asbestos. Chrysotile has the following percent composition: 28.03%

nlexa [21]

Answer: The empirical and molecular formula of chrysotile is $Mg_3Si_2H_3O_4$ and $Mg_6Si_4H_6O_{16}$

Explanation:

We are given:

Percentage of Mg = 28.03 %

Percentage of Si = 21.60 %

Percentage of H = 1.16 %

Percentage of O = 49.21 %

Let the mass of compound be 100 g. So, percentages given are taken as mass.

Mass of Mg = 28.03 g

Mass of Si = 21.60 g

Mass of H = 1.16 g

Mass of O = 49.21 g

To formulate the empirical formula, we need to follow some steps:

Step 1: Converting the given masses into moles.

Moles of Magnesium = $\frac{\text{Given mass of Magnesium}}{\text{Molar mass of Magnesium}}=\frac{28.03g}{24g/mole}=1.17moles$

Moles of Silicon = $\frac{\text{Given mass of Silicon}}{\text{Molar mass of Silicon}}=\frac{21.06g}{28g/mole}=0.752moles$

Moles of Hydrogen = $\frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{1.16g}{1g/mole}=1.16moles$

Moles of Oxygen = $\frac{\text{Given mass of oxygen}}{\text{Molar mass of oxygen}}=\frac{49.21g}{16g/mole}=3.07moles$

Step 2: Calculating the mole ratio of the given elements.

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 0.752 moles.

For Magnesium = $\frac{1.17}{0.752}=1.5$

For Silicon = $\frac{0.752}{0.752}=1$

For Hydrogen = $\frac{1.16}{0.752}=1.5$

For Oxygen = $\frac{3.07}{0.485}=4.08\approx 4$

To convert the mole ratios into whole numbers, we multiply individual mole ratios by 2

Mole ratio of Magnesium = (2 × 1.5) = 3

Mole ratio of Silicon = (2 × 1) = 2

Mole ratio of Hydrogen = (2 × 1.5) = 3

Mole ratio of Oxygen = (2 × 4) = 8

Step 3: Taking the mole ratio as their subscripts.

The ratio of Mg : Si : H : O = 3 : 2 : 3 : 8

The empirical formula for the given compound is $Mg_3Si_2H_3O_8$

For determining the molecular formula, we need to determine the valency which is multiplied by each element to get the molecular formula.

The equation used to calculate the valency is :

$n=\frac{\text{Molecular mass}}{\text{Empirical mass}}$

We are given:

Mass of molecular formula = 520.8 g/mol

Mass of empirical formula = [(24 × 3) + (28 × 2) + (1 × 3) + (16 × 8)] = 259 g/mol

Putting values in above equation, we get:

$n=\frac{520.8g/mol}{259g/mol}=2$

Multiplying this valency by the subscript of every element of empirical formula, we get:

$Mg_{(3\times 2)}Si_{(2\times 2)}H_{(3\times 2)}O_{(8\times 2)}=Mg_6Si_4H_6O_{16}$

Hence, the empirical and molecular formula of chrysotile is $Mg_3Si_2H_3O_4$ and $Mg_6Si_4H_6O_{16}$

5 0

4 years ago

The following ionic compounds are found in common household products. write the formulas for each compound:

victus00 [196]

Answer:

A. Potassium phosphate: K3PO4

B. Copper (II) sulfate: CuSO4

C. Calcium chloride: CaCl2

D. Titanium dioxide: TiO2

E. Ammonium nitrate: NH4NO3

F. Sodium bisulfate: NaHSO4

Explanation:

All are ionic salts with different valent (mono valent cation or poly valent cation and anions) ions.

3 0

3 years ago

If the number of moles of a gas initially contained in a 2.10 l vessel is doubled, what is the final volume of the gas in liters

Anon25 [30]

Avagadro's law gives the relationship between volume of gas and number of moles of the gas. When the temperature and pressure are constant, volume is directly proportional to number of moles of gas.
$\frac{V1}{n1} = \frac{V2}{n2}$
V -volume and n - number of moles of gas.
parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation
initial number of moles n1 - N
n2 - 2N as the number of moles are doubled
V1 - initial volume - 2.10 L
V2 - final volume - V
substituting the values in the equation
$\frac{2.10L}{N} \frac{V}{2N}$
V = 4.20 L
final volume is 4.20 L

7 0

3 years ago