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3 years ago

How can the law of conservation of mass for a chemical reaction be expressed?

Chemistry

1 answer:

djverab [1.8K]3 years ago

5 0

Answer:

The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.

Explanation:

How does the concept of conservation of mass apply to chemical reactions? the reactants and products have exactly the same atoms. the reactants and products have exactly the same molecules. the change in the amount of matter is equal to the change in energy.

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3. A tea kettle holds about of water. 2 mL 200 mL 2L 200 L

cluponka [151]

A tea kettle holds on average about 1.7-2 Liters of water. So the answer should be 2 Liters

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4 years ago

Read 2 more answers

How many moles are in 325mL of 1.25M (NH4)2SO4

mote1985 [20]

Answer:

$n_{solute}=0.406mol(NH_4)_2SO_4$

Explanation:

Hello,

In this case, since the molarity is defined as the ratio of the moles of the solute to the volume of the solution in liters:

$M=\frac{n_{solute}}{V_{solution}}$

For the given volume and molarity, we solve for the moles of ammonium sulfate (solute) as shown below:

$n_{solute}=M*V_{solution}=1.25\frac{mol}{L}*325mL*\frac{1L}{1000mL} \\\\n_{solute}=0.406mol(NH_4)_2SO_4$

Best regards.

4 0

4 years ago

Does his model correctly show why the properties of the ending substances are different from the properties of the starting subs

topjm [15]

Answer:

Samira's model is incorrect because not all atoms are accounted for

Explanation:

The image of Samira's model has been attached to this answer to enhance the explanation.

What is depicted in that model is rightly regarded as a chemical change. In a chemical change atoms of substances are rearranged as new substances are formed.

However, all atoms in the products must also be found in at least one of the reactants. In this case we have an atom in one of the products that is not accounted for. Hence the model is incorrect.

6 0

3 years ago

Find the standard enthalpy of formation of ethylene, C2H4(g), given the following data: C2H4(g) + 3 O2(g) --> 2CO2(g) + 2 H2O

Brums [2.3K]

Answer : The standard enthalpy of formation of ethylene is, 52.4 kJ

Explanation :

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

The formation reaction of $C_2H_4$ will be,

$2C(s)+2H_2(g)\rightarrow C_2H_4(g)$ $\Delta H_{formation}=?$

The intermediate balanced chemical reaction will be,

(1) $C_2H_4(g)+3O_2(g)\rightarrow 2CO_2(g)+2H_2O(l)$ $\Delta H_1=-1411kJ$

(2) $C(s)+O_2(g)\rightarrow CO_2(g)$ $\Delta H_2=-393.5kJ$

(3) $H_2(g)+\frac{1}{2}O_2(g)\rightarrow H_2O(l)$ $\Delta H_3=-285.8kJ$

Now we will reverse the reaction 1, multiply reaction 2 and 3 by 2 then adding all the equation, we get :

(1) $2CO_2(g)+2H_2O(l)\rightarrow C_2H_4(g)+3O_2(g)$ $\Delta H_1=+1411kJ$

(2) $2C(s)+2O_2(g)\rightarrow 2CO_2(g)$ $\Delta H_2=2\times (-393.5kJ)=-787kJ$

(3) $2H_2(g)+2O_2(g)\rightarrow 2H_2O(l)$ $\Delta H_3=2\times (-285.8kJ)=-571.6kJ$

The expression for enthalpy of formation of $C_2H_4$ will be,

$\Delta H_{formation}=\Delta H_1+\Delta H_2+\Delta H_3$

$\Delta H=(+1411kJ)+(-787kJ)+(-571.6kJ)$

$\Delta H=52.4kJ$

Therefore, the standard enthalpy of formation of ethylene is, 52.4 kJ

7 0

3 years ago

Does the model below represent a mixture or a substance ?

Vikentia [17]

Answer:

substance

Explanation:

A mixture is when two or more different atoms/molecules are together, but not joined.

A substance is when the same atom/molecule is in a group together.

In this example, it is a substance because it is comprised of the same molecule not joined all together. If you wanted a mixture, other colored atoms/molecule (e.g. add green atoms) would change it to this property.

4 0

3 years ago