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3 years ago

How are element identified in terms of their atoms

1 answer:

5 0

The mass number is the sum of the numbers of neutrons and protons in the nucleus. The elements can be identified unambiguously by the "spectral fingerprints" of theirline spectra and in some cases by the flame colors given off by excited atoms.

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Determine the number of moles in 382.5g of CO-2

exis [7]

Answer: 8.691 mols of CO₂

Explanation:

To find the number of moles in a given grams, you want to use the molar mass.

Let's first find the molar mass of CO₂.

Carbon's molar mass is 12.011 g/mol

Oxygen's molar mass is 15.999 g/mol

To find molar mass of CO₂, we want to add up the molar mass of carbon and oxygen. Remember, there are 2 Oxygens so we need to mulitply that by 2.

12.011+2(15.999)=44.009 g/mol

Now that we have molar mass, we can convert 382.5 g to mols.

$382.5g*\frac{1 mol}{44.009g} =8.691 mol$

There are about 8.691 mols of CO₂.

5 0

3 years ago

How many grams of magnesium acetate are in 8.95x10^23 formula units?

Natasha_Volkova [10]

Answer:

211.63 g.

Explanation:

Particles could refer to atoms, molecules, formula units.

Knowing that every one mole of a substance contains Avogadro's no. of molecules (NA = 6.022 x 10²³).

Using cross multiplication:

1.0 mole → 6.022 x 10²³ molecules.

??? mole → 8.95 x 10²³ molecules.

The no. of moles of magnesium acetate = (8.95 x 10²³ molecules) (1.0 mole) / (6.022 x 10²³ molecules) = 1.486 mol.

∴ The grams of magnesium acetate are in 8.95 x 10²³ formula units = n x molar mass = (1.486 mol)(142.394 g/mol) = 211.63 g.

5 0

3 years ago

A piece of high-density Styrofoam measuring 24.0 cm by 36.0 cm by 5.0 cm floats when placed in a tub of water. When a 1.5 kg boo

zheka24 [161]

Explanation:

The given data is as follows.

Width of Styrofoam = 24.0 cm

Length of Styrofoam = 36.0 cm

Height of Styrofoam = 5.0 cm

Therefore, volume of the Styrofoam will be calculated as follows.

Volume = length × width × height

= (36.0 × 24.0 × 5.0) $cm^{3}$

= 4320 $cm^{3}$

or, = $4.32 \times 10^{3} cm^{3}$

As Styrofoam partially sinks at 3.0 cm and total height of Styrofoam is 5.0 cm. Hence, height of Styrofoam above the water is (5.0 - 3 cm) = 2 cm.

So, volume of water displaced is as follows.

24.0 cm × 36.0 cm × 2.0 cm

= $1.73 \times 10^{3} cm^{3}$

Hence, mass of displaced water is as follows.

mass = density × volume

= $1.00 g/cm^{3} \times 1.73 \times 10^{3} cm^{3}$

= $1.73 \times 10^{3} g$

Since, book is placed on the Styrofoam. Therefore, mass of water displaced is also equal to the following.

Mass of water displaced = mass of book + mass of Styrofoam

$1.73 \times 10^{3} g$ = 1500 g + mass of Styrofoam

(1730 - 1500) g = mass of Styrofoam

mass of Styrofoam = 230 g

Therefore, calculate the density of Styrofoam as follows.

Density = $\frac{mass}{volume}$

= $\frac{230}{4.32 \times 10^{3} cm^{3}}$

= $53.24 \times 10^{-3} g cm^{-3}$

Thus, we can conclude that the density of Styrofoam is $53.24 \times 10^{-3} g cm^{-3}$ .

4 0

3 years ago

Which of the following list all the elements that are present in a molecule of potassium carbonate K2C03?

meriva

H
Since K stands for potassium, C stands for Carbon and O stands for Oxygen

3 0

3 years ago

Which two phase changes occur when you increase the heat?

muminat

Answer:

Heat going into a substance changes it from a solid to a liquid or a liquid to a gas. Removing heat from a substance changes a gas to a liquid or a liquid to a solid.

Liquid → Gas:

VaporizationGas → Liquid:

CondensationSolid → Liquid:

Melting or fusion

Solid → Gas: Sublimation

Explanation:

8 0

2 years ago