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3 years ago

How many moles are in 68.5 liters of oxygen gas at STP?

2 answers:

7 0

We can solve this problem when we use the conditions of a gas at standard temperature and pressure. It has been established that at STP where the temperature is 0 degrees Celsius and the pressure is 101.325 kPa, the volume of 1 mole of gas is 22.4 L. We will use this data for the calculations.

68.5 L ( 1 mol O2 / 22.4 L O2 ) = 3.06 mol O2

harina [27]3 years ago

5 0

Explanation:

It is known that at STP, there are 22.4 L present in one mole of a substance.

Therefore, in 68.5 liters there will be 1 mol divided by 22.4 L times 68.5 L.

Mathematically, $68.5 L \times \frac{1 mol O_{2}}{22.4 L}$

= 3.05 mol

Hence, we can conclude that there are 3.05 moles present in 68.5 liters of oxygen gas at STP.

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Calculate the number of grams of Mg needed for this reaction to release enough energy to increase the temperature of 78 mL of wa

Vaselesa [24]

Answer:

We need 1.1 grams of Mg

Explanation:

Step 1: Data given

Volume of water = 78 mL

Initial temperature = 29 °C

Final temperature = 78 °C

The standard heats of formation

−285.8 kJ/mol H2O(l)

−924.54 kJ/mol Mg(OH)2(s)

Step 2: The equation

The heat is produced by the following reaction:

Mg(s)+2H2O(l)→Mg(OH)2(s)+H2(g)

Step 3: Calculate the mass of Mg needed

Using the standard heats of formation:

−285.8 kJ/mol H2O(l)

−924.54 kJ/mol Mg(OH)2(s)

Mg(s) + 2 H2O(l) → Mg(OH)2(s) + H2(g)

−924.54 kJ − (2 * −285.8 kJ) = −352.94 kJ/mol Mg

(4.184 J/g·°C) * (78 g) * (78 - 29)°C = 15991.248 J required

(15991.248 J) / (352940 J/mol Mg) * (24.3 g Mg/mol) = 1.1 g Mg

We need 1.1 grams of Mg

7 0

3 years ago

Under what conditions of temperature and pressure is a gas least soluble in water

snow_tiger [21]

The conditions of temperature and pressure in which a gas least soluble in water is low pressure and high temperature.

<h3>What is Henry Law?</h3>

The amount of dissolved gas in a liquid is proportional to its partial pressure above the liquid, according to Henry's law.

From this law it is clear that:

As the pressure of the gas increases solubility of the gas on the liquid also increases.

But if the temperature of the liquid decreases then the solubility of the gas also increases.

Hence at low pressure and high temperature, gas is least soluble.

To know more about solubility of gas, visit the below link:

brainly.com/question/14747303

#SPJ4

7 0

2 years ago

What are the roles of producers, primary consumers, secondary consumers, tertiary consumers for the trophic levels in the energy

Nesterboy [21]

This question is more for Biology than Chemistry, but the role of producers is to make energy (food) to be consumed. In a pyramid diagram, the producers would be at the bottom. Now going up the pyramid, the primary conumers are the first to consume producers and obtain energy from them. As you go up the pyramid, the secondary consumers will consume the primary consumers as a way to obtain energy, and the same goes for tertiary consumers towards secondaries.

As you go up the energy pyramid, you will notice a trend that there is less energy being obtained from each consumer. In other words, the producers will ALWAYS have more energy than the tertiary consumers.

I hope this answers your question.

3 0

3 years ago

Which atom in the ground state has the same electron configuration as a calcium ion, Ca2+, in the ground state?(1) Ar(2) K(3) Mg

Irina-Kira [14]

atoms are made of 3 types of subatomic particles; electrons, protons and neutrons

atomic number is the number of protons. atomic number is characteristic for the element. In ground state atoms, the number of electrons and protons are the same.

the electronic configuration of Ca in the ground state is

Ca - 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²

when Ca loses its 2 valence electrons, it becomes positively charged and the electronic configuration becomes

Ca - 1s² 2s² 2p⁶ 3s² 3p⁶

number of electrons in Ca²⁺ is 18

the atom in the ground state would have the same number of electrons and protons. Therefore number of protons are 18. then the atomic number of the element is 18

the atom having an atomic number of 18 is Ar.

the answer is 1) Ar

7 0

3 years ago

Read 2 more answers

Given the following chemical reaction: 2 O2 + CH4 CO2 + 2 H2O What mass of CH4 is required to completely react with 100 grams of

AfilCa [17]

Answer:

The mass methane (CH4) required is, 25 grams (option C)

Explanation:

Mass of oxygen gas = 100 g

Molar mass of oxygen gas = 32 g/mole

Molar mass of methane gas = 16 g/mole

<u>Step 1:</u> Balance the reaction

2O2 + CH4 → CO2 + 2H2O

<u>Step 2:</u> Calculate the moles of O2:

Moles O2 = mass of O2 / Molar mass of o2

Moles O2 = 100g / (32g/mole) = 3,125 moles

⇒From the balanced reaction we conclude that 2 moles of O2 react with 1 mole of CH4

⇒ So, 3.125 moles of O2 react with 3.125/2 = 1.563 moles of CH4

<u>Step 3:</u> Calculate the mass of CH4:

Mass of CH4 = moles of CH4 x Molar mass of CH4

Mass of CH4 = 1.563 moles / (16g/ moles) = 25.008 grams CH4

6 0

3 years ago