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2 years ago

1. Burning a candle is a chemical change. What is the primary evidence that burning the candle is a chemical reaction?

Chemistry

1 answer:

tankabanditka [31]2 years ago

8 0

<h2>Answer 1) Option B) Temperature Change</h2><h3>Explanation : </h3>

The burning of candle is the reaction where both physical and chemical changes occurs. A physical change where the melted wax is cooled and the wax is obtained again. Whereas the chemical change takes place when the wick of the candle burns using the oxygen in the air and produces heat and light. So, this change in temperature is a chemical change as the burning process cannot be reverse, from the burnt products like soot, smoke and carbon dioxide. Therefore, the temperature change is the evidence of a chemical change in the burning of candle.

<h2>Answer 2) Option B) It is a chemical change because heat energy is absorbed and the pack gets colder.</h2><h3>Explanation :</h3>

When Clara is mixing the vial contents the ice pack gets colder. On application of the ice pack on the injured area absorbs the heat from that region and becomes more colder. This happens because in the ice pack was the medium for the temperature change that was occurring. This temperature change by absorbing heat getting colder is the evidence of a chemical change.

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Two identical containers, one red and one yellow, are inflated with different gases at the same volume and pressure. Both contai

Evgen [1.6K]

Answer:

Explanation:

Here we're dealing with the root mean square velocity of gases. We'll provide the formula in order to calculate the root mean square velocity of a gas:

$v_{rms}=\sqrt{\frac{3RT}{M}}$

Here:

$R = 8.314 \frac{J}{K mol}$ is the ideal gas law constant;

$T$ is the absolute temperature in K;

$M$ is the molar mass of a compound in kg/mol.

We know that the gas from the red container is 4 times faster, as it takes 4 times as long for the yellow container to leak out, this means:

$\frac{v_{rms, red}}{v_{rms, yellow}} = 4$

We also know that the temperature of the red container is twice as large:

$\frac{T_{red}}{T_{yellow}} = 2$

Write the ratio of the velocities and substitute the variables:

$\frac{v_{rms, red}}{v_{rms, yellow}}=\frac{\sqrt{\frac{3RT_{red}}{M_{red}}}}{\sqrt{\frac{3RT_{yellow}}{M_{yellow}}}}=4$

Then:

$\frac{\sqrt{\frac{3RT_{red}}{M_{red}}}}{\sqrt{\frac{3RT_{yellow}}{M_{yellow}}}}=\sqrt{\frac{3RT_{red}}{M_{red}}\cdot \frac{M_{yellow}}{3RT_{yellow}}}=\sqrt{\frac{T_{red}}{T_{yellow}}\cdot \frac{M_{yellow}}{M_{red}}}=4$

From here:

$16 = \frac{T_{red}}{T_{yellow}}\cdot \frac{M_{yellow}}{M_{red}}$

Then:

$\frac{M_{yellow}}{M_{red}} = \frac{16}{\frac{T_{red}}{T_{yellow}}} = \frac{16}{2} = 8$

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3 years ago

What are some important things in this paragraph ???? BRAINLIST WILL BE AWARDED!

mezya [45]

Answer:

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Explanation:

I think this is it tell me if i'm wrong

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2 years ago

When people walked on the Moon, they found that they could jump higher than they could back on Earth. Why is this true?

Allushta [10]

Answer: B

Explanation: the moon is smaller and contains less mass, therefore its gravitational pull is less than that of Earth's.

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2 years ago

What happens when a chemical change occurs

Alona [7]

Chemical change happens when a substance combines with another substance to form a new substance. It produces chemical reactions and generally is not reversible except by further chemical reactions. Heat is sometimes produced in some reactions. When chemical reactions occur, the atoms are rearranged and an energy change happens along with it as new products are generations. At a molecular level, chemical changes involves the making or breaking of bonds between atoms. Some examples of chemical change are iron rusting (iron oxide forms) and bread rising (yeast converts carbohydrates into carbon dioxide gas).

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2 years ago

Read 2 more answers

Calculate the osmotic pressure of a solution containing 24.6g of glycerin in 250ml of solution at 298K

gavmur [86]

The formula to calculate osmotic pressure is
Osmotic Pressure = M R T
M = Molarity
R = Ideal Gas Constant
T = Temperature in Kelvin

So,
24.6/.2254kg=109.139g /kg >>>>> Molarity
109.139 x mols/92 g = 1.186 mols kg^-1
1.186 x 0.08134 x 298 K = 28.755 atm
<span>1.06852 x 0.08134 x 298K= 26.5 atm

The answer is 26.5</span>

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3 years ago