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3 years ago

15

The heaviest commonly used United States coin is the half dollar, which has a mass of 11.340g. The lightest United States coin i

s the dime, which has a mass of 2.268 g. Report the sum of these masses in scientific notation

1 answer:

Kruka [31]3 years ago

7 0

Answer:

13.6×10^3

Explanation:

11.340+2.268= 13.608

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A sample of ammonia gas was allowed to come to equilibrium at 400 K. 2NH3(g) <---> N2(g) 3H2(g) At equilibrium, it was fou

Softa [21]

Answer:

Kc for this equilibrium is 2.30*10⁻⁶

Explanation:

Equilibrium occurs when the rate of the forward reaction equals the rate of the reverse reaction and the concentrations of reactants and products are held constant.

Being:

aA + bB ⇔ cC + dD

the equilibrium constant Kc is defined as:

$Kc=\frac{[C]^{c}*[D]^{d} }{[A]^{a} *[B]^{b} }$

In other words, the constant Kc is equal to the multiplication of the concentrations of the products raised to their stoichiometric coefficients by the multiplication of the concentrations of the reactants also raised to their stoichiometric coefficients. Kc is constant for a given temperature, that is to say that as the reaction temperature varies, its value varies.

In this case, being:

2 NH₃(g) ⇔ N₂(g) + 3 H₂(g)

the equilibrium constant Kc is:

$Kc=\frac{[N_{2} ]*[H_{2} ]^{3} }{[NH_{3} ]^{2} }$

Being:

[N₂]= 0.0551 M
[H₂]= 0.0183 M
[NH₃]= 0.383 M

and replacing:

$Kc=\frac{0.0551*0.0183^{3} }{0.383^{2} }$

you get:

Kc= 2.30*10⁻⁶

<u><em>Kc for this equilibrium is 2.30*10⁻⁶</em></u>

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3 years ago

How do scientists measure the idea of time so long ago?

professor190 [17]

The Ancient Egyptians used simple sundials and divided days into smaller parts, and it has been suggested that as early as 1,500BC, they divided the interval between sunrise and sunset into 12 parts. ... Known as a clepsydra, it uses a flow of water to measure time.

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2 years ago

6. Explain the impact on fresh water of:

Paraphin [41]

Fresh water pollutants are substances which pollute fresh water and industrial waste, is most harmful fresh water pollutant to man and aquatic organisms.

<h3>What are pollutants?</h3>

Pollutants are substances which cause harm when they are present in the environment.

Pollutants include chemicals such as petroleum and material such as sewage.

The presence of pollutants in freshwater results in water pollution and make the water unfit for drinking purposes and also harms aquatic life in freshwaters.

Some freshwater pollutants include:

Farming wastes
Household pollutants
Industrial wastes
Erosion
Oil and Gasoline
heat

Of these pollutants, the most dangerous fresh water pollutant is industrial wastes as they kill aquatic organisms most due to the presence of harmful chemicals in them.

Therefore, fresh water pollutants such as industrial waste is most harmful to man and aquatic organisms.

Learn more about pollutants at: brainly.com/question/1235358

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1 year ago

The complete combustion of propane (C3H8) in the presence of oxygen yields CO2 and H2O: C3H8 (g) + 5O2 (g) 3CO2 (g) + 4H2O (g) a

mixas84 [53]

Answer:

26.9 L is the volume of CO₂, we obtained

Explanation:

The reaction is: C₃H₈(g) + 5O₂(g) → 3CO₂ (g) + 4H₂O (g)

Let's determine the reactants moles:

27.5 g . 1mol / 44 g = 0.625 moles

We need density of O₂ to determine mass and then, the moles.

O₂ density = O₂ mass / O₂ volume

O₂ density . O₂ volume = O₂ mass

1.429 g/L . 45L = O₂ mass → 64.3 g

Moles of O₂ → 64.3 g . 1mol/32g = 2.009 moles

Let's find out the limiting reactant:

1 mol of propane needs 5 moles of oxygen to react

Then, 0.625 moles will react with (0.625 . 5)/1 = 3.125 moles of O₂

Oxygen is the limiting reactant, we need 3.125 moles but we only have 2.009 moles

Ratio is 5:3. 5 moles of O₂ produce 3 moles of CO₂

Therefore, 2.009 moles of O₂ must produce (2.009 .3) /5 = 1.21 moles of CO₂. Let's find out the volume, by Ideal Gases Law (STP are 1 atm and 273K, the standard conditions)

1 atm . V = 1.21 moles . 0.082 . 273K

V = (1.21 moles . 0.082 . 273K) / 1atm = 26.9 L

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3 years ago

Which of the following is not an ingredient for photosynthesis?

Katarina [22]

Answer:

d

Explanation:

......................

4 0

2 years ago

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