Answer:
46.40 g.
Explanation:
- It is a stichiometric problem.
- The balanced equation of the reaction: 4K + O₂ → 2K₂O.
- It is clear that 4.0 moles of K reacts with 1.0 mole of oxygen produces 2.0 moles of K₂O.
- We should convert the mass of K (38.5 g) into moles using the relation:
<em>n = mass / molar mass,</em>
n = (38.5 g) / (39.098 g/mol) = 0.985 mole.
<em>Using cross multiplication:</em>
4.0 moles of K produces → 2.0 moles of K₂O, from the stichiometry.
0.985 mole of K produces → ??? moles of K₂O.
∴ The number of moles of K₂O produced = (0.985 mole) (2.0 mole) / (4.0 mole) = 0.4925 mole ≅ 0.5 mole.
- Now, we can get the mass of K₂O:
∴ mass = n x molar mass = (0.5 mole) (94.2 g/mol) = 46.40 g.
Answer:
the moluculer formula is the answer
Explanation:
Answer:
Name the element: Beryllium
Number of shells: 4
Valence electrons: 2
Explanation:
24.6 ℃
<h3>Explanation</h3>
Hydrochloric acid and sodium hydroxide reacts by the following equation:
which is equivalent to
The question states that the second equation has an enthalpy, or "heat", of neutralization of 
. Thus the combination of every mole of hydrogen ions and hydroxide ions in solution would produce 
or 
of energy.
500 milliliter of a 0.50 mol per liter "M" solution contains 0.25 moles of the solute. There are thus 0.25 moles of hydrogen ions and hydroxide ions in the two 0.500 milliliter solutions, respectively. They would combine to release 
of energy.
Both the solution and the calorimeter absorb energy released in this neutralization reaction. Their temperature change is dependent on the heat capacity <em>C</em> of the two objects, combined.
The question has given the heat capacity of the calorimeter directly.
The heat capacity (the one without mass in the unit) of water is to be calculated from its mass and <em>specific</em> heat.
The calorimeter contains 1.00 liters or 
of the 1.0 gram per milliliter solution. Accordingly, it would have a mass of 
.
The solution has a specific heat of 
. The solution thus have a heat capacity of 
. Note that one degree Kelvins K is equivalent to one degree celsius ℃ in temperature change measurements.
The calorimeter-solution system thus has a heat capacity of 
, meaning that its temperature would rise by 1 degree celsius on the absorption of 4.634 × 10³ joules of energy. 
are available from the reaction. Thus, the temperature of the system shall have risen by 3.03 degrees celsius to 24.6 degrees celsius by the end of the reaction.
