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olasank [31]
3 years ago
14

An elementary classroom models a volcanic eruption by mixing vinegar and baking soda. Which of the following observations is not

evidence of a chemical reaction?
Select one:

Gas bubbles formed after the vinegar and baking soda are combined.

After the substances are combined, a salt and water were formed.

The mass of the combined substances is greater then the masses of the substances separately.

The temperature of the combined vinegar and baking soda is less than the substances separately.
Chemistry
1 answer:
kvv77 [185]3 years ago
7 0
C is not an example.

explanation: Mass is a physical property as the law of conservation of mass states mass is neither created nor destroyed in a chemical reaction or physical transformation. Chemical reactions are a change in the molecular structure of the product.
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How many hydrogen molecules are there in 1 ton of hydrogen?​
zaharov [31]
Hydrogen gas(H2) has a molar mass of 2 g. Molar mass of a substance is defined as the mass of 1 mole of that substance. And by 1 mole it is meant a collection of 6.022*10^23 particles of that substance.

So number of moles of H2 are 0.5 in this case. And thus it means there are (6.022*10^23)*0.5 particles( here they are molecules) in 1g of H2.
6 0
2 years ago
ethylene glycol used in automobile antifreeze and in the production of polyester. The name glycol stems from the sweet taste of
Luden [163]

<u>Answer:</u> The empirical and molecular formula for the given organic compound is CH_3O and C_4H_{12}O_4

<u>Explanation:</u>

The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:

C_xH_yO_z+O_2\rightarrow CO_2+H_2O

where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and oxygen respectively.

We are given:

Mass of CO_2=9.06g

Mass of H_2O=5.58g

We know that:

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

  • <u>For calculating the mass of carbon:</u>

In 44g of carbon dioxide, 12 g of carbon is contained.

So, in 9.06 g of carbon dioxide, \frac{12}{44}\times 9.06=2.47g of carbon will be contained.

  • <u>For calculating the mass of hydrogen:</u>

In 18g of water, 2 g of hydrogen is contained.

So, in 5.58 g of water, \frac{2}{18}\times 5.58=0.62g of hydrogen will be contained.

  • Mass of oxygen in the compound = (6.38) - (2.47 + 0.62) = 3.29 g

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

  • <u>Step 1:</u> Converting the given masses into moles.

Moles of Carbon =\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{2.47g}{12g/mole}=0.206moles

Moles of Hydrogen = \frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{0.62g}{1g/mole}=0.62moles

Moles of Oxygen = \frac{\text{Given mass of oxygen}}{\text{Molar mass of oxygen}}=\frac{3.29g}{16g/mole}=0.206moles

  • <u>Step 2:</u> 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 0.206 moles.

For Carbon = \frac{0.206}{0.206}=1

For Hydrogen  = \frac{0.62}{0.206}=3

For Oxygen  = \frac{0.206}{0.206}=1

  • <u>Step 3:</u> Taking the mole ratio as their subscripts.

The ratio of C : H : O = 1 : 3 : 1

Hence, the empirical formula for the given compound is C_1H_{3}O_1=CH_3O

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 = 124 amu = 124 g/mol

Mass of empirical formula = 31 g/mol

Putting values in above equation, we get:

n=\frac{124g/mol}{31g/mol}=4

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

C_{(1\times 4)}H_{(3\times 4)}O_{(1\times 4)}=C_4H_{12}O_4

Thus, the empirical and molecular formula for the given organic compound is CH_3O and C_4H_{12}O_4

3 0
2 years ago
The compound AX2 decomposes according to the equation, 2 AX2(g) =&gt; 2 AX(g) + X2(g). In one experiment, AX2 was measured at va
Karolina [17]

Answer:

0.0011 mol/L.s

Explanation:

The average rate of disappearing of the reagent is the variation of the concentration of it divided by the time that this variation is being measured. The reaction rate, is proportional to the coefficient of the substance, so, for a generic reaction:

aA + bB --> cC + dD

rate = -(1/a)Δ[A]/Δt = -(1/b)Δ[B]/Δt = (1/c)Δ[C]/Δdt = (1/d)Δ[D]/dt

The minus sign is because of the reagent is desapering, so:

rate = -(1/2)*(0.0209 - 0.0300)/(10 - 6)

rate = 0.0011 mol/L.s

8 0
2 years ago
How many molecules are in 70.7 grams of C4H10?
OlgaM077 [116]

Answer:

1.216mol

Explanation:

The molar mass of C₄H₁₀ is (12 x4)+ (1x 10) = 48 + 10 = 58g

1 grams C4H10 is equal to 0.017205129881525 mole.

70.7 grams = 70.7 x 0.017205129881525  = 1.216mol

6 0
2 years ago
Read 2 more answers
A 3.140 molal solution of NaCl is prepared. How many grams of NaCl are present in a sample containing 2.314 kg of water?
Mariulka [41]

Answer:

g NaCl = 424.623 g

Explanation:

<em>C</em> NaCl = 3.140 m = 3.140 mol NaCl / Kg solvent

∴ solvent: H2O

∴ mass H2O = 2.314 Kg

mol NaCl:

⇒ mol NaCl = (3.140 mol NaCl/Kg H2O)×(2.314 Kg H2O) = 7.266 mol NaCl

∴ mm NaCl = 58.44 g/mol

⇒ g NaCl = (7.266 mol NaCl)×(58.44 g/mol) = 424.623 g NaCl

5 0
2 years ago
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