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3 years ago

Which of these rocks forms from lava that cools very quickly?

Chemistry

1 answer:

den301095 [7]3 years ago

4 0

The answer is D. obsidian. Or at least I think it is. Just guessing based off me playing Minecraft 6 years ago haha

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The reaction of hydrogen(g) with fluorine(g) to form hydrogen fluoride(g) proceeds as follows: H2(g) + F2(g) 2 HF(g) When 0.647

Nata [24]

Answer: The value of $\Delta H$ for the reaction will be -537 kJ

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of hydrogen gas = 0.647 g

Molar mass of hydrogen gas = 2 g/mol

Putting values in above equation, we get:

$\text{Moles of hydrogen gas}=\frac{0.647g}{2g/mol}=0.324mol$

We are given:

Energy released for 0.324 moles of hydrogen reacted is 174 kJ

For the given chemical reaction:

$H_2(g)+F_2(g)\rightarrow 2HF(g)$

By Stoichiometry of the reaction:

When 0.324 moles of hydrogen gas is reacted, the energy evolved is 174 kJ

So, when 1 mole of hydrogen gas will react, the energy evolved will be = $\frac{174kJ}{0.324mol}\times 1mol=537kJ$

Sign convention of heat:

When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.

Hence, the value of $\Delta H$ for the reaction will be -537 kJ

6 0

3 years ago

Which term represents a chemical reaction?

Marizza181 [45]

Answer:

vaporization

Explanation:

7 0

3 years ago

The number of protons in an atom's nucleus determines its

Nataly [62]

Number of proton present in the nucleus determines the atomic number of an element. It determines chemical properties, which is why all atoms with proton count (atomic number) 6 are carbon

8 0

3 years ago

Read 2 more answers

Explain why scientists find the particulate matter of theory useful

BARSIC [14]

This idea has historical significance. The ancient Greek philosopher Democritus (born 460 BCE), who held that everything is composed of small particles moving in empty space, is credited with developing the first hypothesis we have about the microscopic universe. He had some concrete proof for this, such the fact that items like a new loaf of bread or a rose may give off a scent even when they are far from the source. Being a materialist, he thought that these odors originated from actual material particles released by the bread or the rose, rather than being purely a type of magic. He reasoned that these particles must float through the air, with some of them maybe landing in your nose where you can smell them immediately. This still makes sense in modern times. But many of us now have quite different perspectives on these "particles."

Thank you,

Eddie

6 0

2 years ago

Why does pumping more air into a basketball increse the pressure inside the ball?

scoundrel [369]

Think of it as a balloon when you pump air into it it grows bigger but, if you put too much air into it what happens it pops because the pressure was too much for the balloon to withhold. That's the same with a basketball when you pump air into it the pressure pushing on the material increases.

8 0

3 years ago