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3 years ago

Two examples of energy transformations are shown.

Chemistry

2 answers:

erastova [34]3 years ago

5 0

The energy transformations are similar because they result into radiant energy.

As for the lamp, Electrical energy is transformed into light when the filament

or mercury vapor glows on passage of current.

The fire- chemical energy is turned to light energy during the combustion of carbon. Both products comprise of ultraviolet radiation which is a form of radiant energy.

Tom [10]3 years ago

4 0

Answer:

Explanation:

Just took the test

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PLEASE HELP.Which of these substances will dissolve in water?

Alex17521 [72]

Answer:

A. Sugar

Explanation:

Sugar dissolves in water because of its molecular structure (C6H12O6), as the sugar is put in the water, energy is released and the polarity of the water breaks apart the molecules. However, the molecules can be obtained back by evaporating the water.

5 0

2 years ago

Use the following information to determine the empirical formula if a compound is found to have 18.7% Li, 16.3% C, and 65.5% O A

Elina [12.6K]

Answer:

The empirical formula is Li2CO3

Explanation:

Step 1: Data given

Suppose the mass of the compound = 100 grams

The compound contains :

18.7% Li = 18.7 grams of Li

16.3 % C = 16.3 grams of C

65.0% O = 65.0 grams of O

Total = 100%

Molar mass of Li = 6.94 g/mol

Molar mass of C = 12.01 g/mol

Molar mass of O = 16 g/mol

Step 2: Calculate moles

Moles = Mass / molar mass

Moles Li = 18.7 grams / 6.94 g/mol = 2.65 moles

Moles C = 16.3 grams / 12.01 = 1.36 moles

Moles O = 65.0 grams / 16.0 g/mol = 4.06 moles

Step 3: Calculate the mol ratio

We divide by the smallest number of moles

Li: 2.65/1.36 ≈ 2

C: 1.36/1.36 = 1

O: 4.06/1.36 ≈ 3

The empirical formula is Li2CO3

3 0

3 years ago

Farmers who raise cotton once used arsenic acid, H3AsO4, as a defoliant at harvest time. Arsenic acid is a polyprotic acid with

Bess [88]

Answer:

pH = 1.95

Explanation:

For polyprotic acids, it is generally assumed that all H⁺ comes from the 1st ionization step. The amount of H⁺ delivered into solution for the 2nd and 3rd ionization steps are in the order of 10⁻⁴M and 10⁻⁶M respectively and provide very little change in pH from the quantity delivered in the 1st ionization step.

Therefore... the [H⁺] concentraion and pH are computed as follows...

[H⁺] = √Ka₁[H₃AsO₄] = √(2.5 x 10⁻⁴)(0.500) M = 0.1118M

pH = -log[H⁺] = -log(0.01118) = 1.95

8 0

3 years ago

A sample of octane undergoes combustion according to the equation 2 C8H18 + 25 O2 → 16 CO2 + 18 H2O ΔH°rxn = -11018 kJ. What mas

Anna71 [15]

Answer:

$\large \boxed{\text{528.7 g} }$

Explanation:

It often helps to write the heat as if it were a reactant or a product in the thermochemical equation.

Then you can consider it to be 11018 "moles" of "kJ"

We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.

M_r: 32.00

2C₈H₁₈ + 25O₂ ⟶ 16CO₂ + 8H₂O + 11 018 kJ

n/mol: 7280

1. Moles of O₂

The molar ratio is 25 mol O₂:11 018 kJ

$\text{Moles of O}_{2} = \text{7280 kJ} \times \dfrac{\text{25 mol O}_{2}}{\text{11 018 kJ}} = \text{16.52 mol O}_{2}$

2. Mass of O₂

$\text{Mass of C$_{8}$H}_{18} = \text{16.52 mol O}_{2} \times \dfrac{\text{32.00 g O}_{2}}{\text{1 mol O}_{2}} = \textbf{528.6 g O}_{2}\\\text{The reaction requires $\large \boxed{\textbf{528.67 g O}_{2}}$}$

3 0

3 years ago

Adding water to a concentrated stock solution results in the...?

SOVA2 [1]

Answer:

The solution becomes diluted.

Explanation:

When you add water to a solution, the number of moles of the solvent stays the same while the volume increases. Therefore, the molarity decreases.

Hope this helps!

5 0

3 years ago