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3 years ago

Can someone please answer this?

Chemistry

2 answers:

Blizzard [7]3 years ago

7 0

Answer:

Either A or B

Explanation: Because I learned it on Edge. :)

Lelechka [254]3 years ago

6 0

Answer:

B) go look on the periodic table for the atomic number

Explanation:

The atomic number is how many protons is in an atom

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What is the molecular description of diffusion? the transfer of energy between the moving molecules the constant, organized mole

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The random molecular movement from higher concentration to lower concentration

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3 years ago

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A fuel was burned for 5 min, increasing the temperature of 10.0 g of water with a density of 1.00 g/ml by 9.0 oC. The fuel relea

jekas [21]

The fuel released 90 calories of heat.

Let suppose that water experiments an entirely sensible heating. Hence, the heat released by the fuel is equal to the heat absorbed by the water because of principle of energy conservation. The heat released by the fuel is expressed by the following formula:

$Q = m\cdot c \cdot \Delta T$ (1)

Where:

$m$ - Mass of the sample, in grams.
$c$ - Specific heat of water, in calories per gram-degree Celsius.
$\Delta T$ - Temperature change, in degrees Celsius.

If we know that $m = 10\,g$ , $c = 1\,\frac{cal}{g\cdot ^{\circ}C}$ and $\Delta T = 9\,^{\circ}C$ , then the heat released by the fuel is:

$Q = (10\,g)\cdot \left(1\,\frac{cal}{g\cdot ^{\circ}C} \right)\cdot (9\,^{\circ}C)$

The fuel released 90 calories of heat.

We kindly invite to check this question on sensible heat: brainly.com/question/11325154

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2 years ago

A student wants to measure the entropy of ice. What should the student do?

Helen [10]

Answer: Option (c) is the correct answer.

Explanation:

Entropy is defined as the degree of randomness. This means that more is the number of collisions taking place between atoms of a substance more will be the randomness.

Therefore, more will be the entropy of substance. We cannot measure the entropy but we can measure the change in entropy of a substance.

A thermometer is a glass tube that contains a liquid column generally mercury, and it is usually used to measure the temperature of human body.

A calorimeter is a device or apparatus that is used in a chemical reaction to measure the amount of heat involved.

Therefore, we can conclude that the student can't measure entropy directly, only an entropy change.

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3 years ago

A sample of sodium sulfite has a mass of 2.80 g.

Gnom [1K]

Answer:

For a: The number of sodium ions in given amount of sodium sulfite are $2.65\times 10^{22}$

For b: The number of sulfite ions in given amount of sodium sulfite are $1.325\times 10^{22}$

For c: The mass of one formula unit of sodium ions is $2.09\times 10^{-22}$ grams

Explanation:

The chemical formula of sodium sulfite is $Na_2SO_3$ . It is formed by the combination of 2 sodium $(Na^+)$ ions and 1 sulfite $(SO_3^{2-})$ ions

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

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

Given mass of sodium sulfite = 2.80 g

Molar mass of sodium sulfite = 126 g/mol

Putting values in above equation, we get:

$\text{Moles of sodium sulfite}=\frac{2.80g}{126g/mol}=0.022mol$

For a:

Moles of sodium ions in sodium sulfite = (2 × 0.022) moles

According to mole concept:

1 mole of a compound contains $6.022\times 10^{23}$ number of particles

So, 0.022 moles of sodium sulfite will contain = $(2\times 0.022\times 6.022\times 10^{23})=2.65\times 10^{22}$ number of sodium ions

Hence, the number of sodium ions in given amount of sodium sulfite are $2.65\times 10^{22}$

For b:

Moles of sulfite ions in sodium sulfite = (1 × 0.022) moles

According to mole concept:

1 mole of a compound contains $6.022\times 10^{23}$ number of particles

So, 0.022 moles of sodium sulfite will contain = $(1\times 0.022\times 6.022\times 10^{23})=1.325\times 10^{22}$ number of sulfite ions

Hence, the number of sulfite ions in given amount of sodium sulfite are $1.325\times 10^{22}$

For c:

Molar mass of sodium sulfite = 126 g/mol

According to mole concept:

$6.022\times 10^{23}$ number of formula units are present in 1 mole of a compound

Or, $6.022\times 10^{23}$ number of formula units of sodium sulfite have a mass of 126 grams

So, 1 formula unit of sodium sulfite will have a mass of = $\frac{126}{6.022\times 10^{23}}\times 1=2.09\times 10^{-22}g$

Hence, the mass of one formula unit of sodium ions is $2.09\times 10^{-22}$ grams

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3 years ago

How many atoms of magnesium metal are needed to produce 3.87 moles of magnesium oxide

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Answer:

48.42g of Mg

Explanation:

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