Hydrogen and helium in the universe were formed by which of these phenomena?

1.00g of a metallic element reacts completely with 300cm3 of oxygen at 298K and 1 atm pressure to form an oxide which contains O

elena55 [62]

Answer:

The metal is most likely calcium which has a molar mass of 40.078 g

<em>Note: The question is incomplete. The complete question is given below:</em>

1.00g of a metallic element reacts completely with 300cm3 of oxygen at 298K and 1 atm pressure to form an oxide which contains O2– ions. The volume of one mole of gas at this temperature and pressure is 24.0dm3 .

What could be the identity of the metal?

<em>A calcium B magnesium C potassium D sodium</em>

Explanation:

Number of moles of the oxygen gas reacted is first determined:

Volume of oxygen gas = 300 cm³ = 0.30 dm³

1 mole of a gas occupies 24.0 dm³ at this temperature and pressure

Number of moles of oxygen gas that will occupy 0.30 dm³ = 0.3/24 = 0.125 moles

Let M be represent the metallic element. The equation of the reaction will be:

2M + O₂ ----> 2MO

From the equation of reaction;

2 moles of the metal reacts with 1 mole of oxygen gas

2 * 0.125 moles of the metal will react with 300 cm³ of oxygen = 0.025 moles

Since the mass of the metal that reacted with oxygen is 1.0 g, therefore, 1.0 g of the metal = 0.025 moles

mass of 1 mole of the metal = 1 /0.025 = 40.0 g

Therefore, the metal is most likely calcium which has a molar mass of 40.078 g

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One mole of an ideal gas is contained in a cylinder with a movable piston. The temperature is constant at 77°C. Weights are remo

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Answer:

The total work is 4957.45J

Explanation: