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2 years ago

Best answer and explanation will get marked brainiest

Chemistry

1 answer:

Darina [25.2K]2 years ago

4 0

The number 345,000 has 3 significant figures because the trailing zeros are not significant since there's no decimal point.

<h3>What is significant figures?</h3>

Significant figures of a number in positional notation are digits in the number that are reliable and necessary to indicate the quantity of something.

Also significant figures can be defined as, the number of digits in a value, often a measurement, that contribute to the degree of accuracy of the value.

Examples of significant figures;

405 = 3 significant figures
405000 = 3 significant
0.040500 = 5 significant figures

Note: leading zeros are not significant but trailing zeros, which are zeros at the end of a number, are significant only if the number has a decimal point.

345,000 = 3.45 x 10⁵ (3 significant figures)

Thus, the number 345,000 has 3 significant figures because the trailing zeros are not significant since there's no decimal point.

Learn more about significant figures here: brainly.com/question/24491627

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Brut [27]

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3 years ago

True or False When the attraction between the particles overcomes their motion the particles clump together to boil.

bixtya [17]

Answer:

False

Explanation:

It is wrong to claim that when the attraction between particles overcomes their motion, the particles will clump together to boil.

During boiling particles do no clump together, they tend to move apart more rapidly.

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3 years ago

In the chemical formula below, how many H atoms are present? SNH4OH

saul85 [17]

Answer:

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3 years ago

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

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3 years ago

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Andre45 [30]

Answer:

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Explanation:

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