Connie and Dwayne combine 78 g potassium with 36 g of water. Why would they expect the total mass of the product to be why?
Connie and Dwayne would not expect the total mass of the product to be 78 g + 36 g = 114 g. This is because when potassium reacts with water, it undergoes a chemical reaction that forms potassium hydroxide (KOH) and hydrogen gas (H2). The hydrogen gas is released as a product and does not contribute to the total mass. Therefore, the total mass of the product would be less than 114 g and would mainly consist of potassium hydroxide. The exact mass of the potassium hydroxide would depend on the extent of the reaction and any other side reactions that might occur.
When combining potassium with water, a chemical reaction occurs, resulting in the formation of potassium hydroxide and the release of hydrogen gas. This reaction is highly exothermic and produces a lot of heat.
The total mass of the product would be expected to be less than the sum of the masses of the potassium and water initially combined. This is due to the release of hydrogen gas as a product of the reaction. Hydrogen gas is much lighter than the reactants (potassium and water), so when it is released, it contributes to a decrease in overall mass.
Additionally, the reaction between potassium and water is highly exothermic, meaning it releases a significant amount of energy in the form of heat. Some of the mass may be lost as heat during the reaction.
Therefore, due to the release of hydrogen gas and the loss of some mass as heat energy, Connie and Dwayne would expect the total mass of the product to be less than the combined mass of the potassium and water initially used.
To determine why Connie and Dwayne would expect the total mass of the product to be a certain value, we need to understand the concept of the law of conservation of mass. According to this law, the total mass of substances before a chemical reaction is equal to the total mass of substances after the reaction.
In this case, potassium and water are combining to form a product. When potassium reacts with water, it undergoes a chemical reaction to produce potassium hydroxide (KOH) and hydrogen gas (H2). The balanced chemical equation for this reaction is:
2K + 2H2O -> 2KOH + H2
Now, let's calculate the expected total mass of the product. We have 78 g of potassium and 36 g of water.
The molar mass of potassium (K) is approximately 39.10 g/mol, and the molar mass of water (H2O) is approximately 18.02 g/mol.
First, calculate the number of moles of potassium and water:
Number of moles potassium = mass of potassium / molar mass of potassium
Number of moles potassium = 78 g / 39.10 g/mol
Number of moles potassium ≈ 1.996 mol (rounded to three decimal places)
Number of moles water = mass of water / molar mass of water
Number of moles water = 36 g / 18.02 g/mol
Number of moles water ≈ 1.997 mol (rounded to three decimal places)
According to the balanced chemical equation, 2 moles of potassium react with 2 moles of water to produce 1 mole of potassium hydroxide (KOH) and 1 mole of hydrogen gas (H2).
Since the reaction is balanced in terms of moles, we can conclude that the number of moles of the product, KOH, will be the same as the number of moles of the reactants, potassium and water.
Therefore, the expected mass of the product, KOH, can be calculated as follows:
Mass of KOH = number of moles of KOH × molar mass of KOH
Given that we have 1.996 moles of potassium and 1.997 moles of water, the expected mass of KOH can be calculated as:
Mass of KOH = (1.996 mol + 1.997 mol) × molar mass of KOH
To find the molar mass of KOH, we add the atomic masses of potassium (39.10 g/mol), oxygen (16.00 g/mol), and hydrogen (1.01 g/mol):
Molar mass of KOH = 39.10 g/mol (K) + 16.00 g/mol (O) + 1.01 g/mol (H)
Molar mass of KOH = 56.11 g/mol
Now we can calculate the expected mass of KOH:
Mass of KOH ≈ (1.996 mol + 1.997 mol) × 56.11 g/mol
Mass of KOH ≈ 199.91 g
Therefore, Connie and Dwayne would expect the total mass of the product, which is potassium hydroxide (KOH), to be approximately 199.91 grams.