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3 years ago

A bar of gold is 5.0mm thick, 10.0cm long and 2.0cm wide. It has a mass of exactly 193.0g. What is the desity of gold?

Chemistry

1 answer:

Tanzania [10]3 years ago

3 0

<h3>Answer:</h3>

19.3 g/cm³

<h3>Explanation:</h3>

Density of a substance refers to the mass of the substance per unit volume.

Therefore, Density = Mass ÷ Volume

In this case, we are given;

Mass of the gold bar = 193.0 g

Dimensions of the Gold bar = 5.00 mm by 10.0 cm by 2.0 cm

We are required to get the density of the gold bar

Step 1: Volume of the gold bar

Volume is given by, Length × width × height

Volume = 0.50 cm × 10.0 cm × 2.0 cm

= 10 cm³

Step 2: Density of the gold bar

Density = Mass ÷ volume

Density of the gold bar = 193.0 g ÷ 10 cm³

= 19.3 g/cm³

Thus, the density of the gold bar is 19.3 g/cm³

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Define molecular formula and empirical formula. What are the similarities and differences between the empirical formula and mole

irga5000 [103]

<u>Explanation:</u>

Molecular formula is the chemical formula which depicts the actual number of atoms of each element present in the compound.

Empirical formula is the simplest chemical formula which depicts the whole number of atoms of each element present in the compound.

In both the formulas, the nature of atoms remains the same but the number differs.

For Example: The molecular formula of oxalic acid is $C_2H_2H_4$ but the empirical formula of oxalic acid is $CHO_2$

To calculate the molecular formula, we need to find the valency which is multiplied by each element to get the molecular formula.

The equation used to calculate the valency is:

$n=\frac{\text{Molecular mass}}{\text{Empirical mass}}$

The empirical mass can be calculated from empirical formula and molar mass must be known.

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3 years ago

Where is most of Earth’s fresh water found?

puteri [66]

Answer:

ice caps and glaciers

Explanation:

Over 68 percent of the fresh water on Earth is found in icecaps and glaciers, and just over 30 percent is found in ground water. Only about 0.3 percent of our fresh water is found in the surface water of lakes, rivers, and swamps.

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3 years ago

Read 2 more answers

How many moles are there in 2.00 x 10^19 molecules of CCl4

HACTEHA [7]

Answer: 0.0000332mol

Explanation: 1mole of CCl4 contains 6.02x10^23 molecules.

Therefore, X mol of CCl4 will contain 2 x 10^19 molecules i.e

Xmol of CCl4 = 2 x 10^19/ 6.02x10^23 = 0.0000332mol

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3 years ago

Wine has a pH of 3, which means it is __________ times more acidic than tomatoes, which have a pH of 4.

Natasha2012 [34]

Answer:

Explanation:

pH is defined as the negative logarithm of the concentration of hydrogen ions.

Thus,

pH = - log [H⁺]

Thus, from the formula, more the concentration of the hydrogen ions or more the acidic the solution is, the less is the pH value of the solution.

Thus, solution with pH = 3 will be more acidic than solution with pH =4

Thus, concentration of the [H⁺] when pH =3

3 = - log [H⁺]

[H⁺] = 10⁻³ M

For pH = 4, [H⁺] = 10⁻⁴ M

<u>hence, pH = 3 is 10 times more acidic than pH = 4</u>

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3 years ago

How many molecules are in 42.3g sample of water

Helga [31]

Answer:

The number of molecules is 1.4140*10^24 molecules

Explanation:

To know the number of molecules, we need to determine how many moles of water we have, water has molar mass of 18.015g/mol

This means that one mole of water molecules has a mass of 18.015g.

42.3g * 1 mole H2O/18.015g

= 2.3480 moles H2O

We are using avogadros number to find the number of molecules of water

2.3480 H2O * 6.022*10^ 23moles/ 1mole of H2O

That's 2.3480 multiplied by 6.022*10^23 divided by 1 mole of H2O

Number of molecules = 1.4140 *10^24 molecules

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3 years ago