what is the minimum of amount of KCN in moles needed to extract 29 grams of gold
Au + 2CN^- ==> Au(CN)-2</sub)
Convert 28g Au to mols. mol = grams/atomic mass.
Use the coefficients to convert mols Au to mols CN^-(KCN).
Then convert mols KCN to grams. g = mols x molar mass.
To determine the minimum amount of KCN needed to extract 29 grams of gold, we need to use stoichiometry, which involves converting the given mass of gold to moles and then using the balanced chemical equation to find the mole ratio between KCN and gold.
The molar mass of gold (Au) is 197 grams/mole.
Step 1: Convert the mass of gold to moles.
Number of moles of gold = mass / molar mass
= 29 grams / 197 grams/mole
≈ 0.1472 moles
Step 2: Use the balanced chemical equation to find the mole ratio between KCN and gold.
The balanced chemical equation for the extraction of gold using KCN is as follows:
2 KCN + Au → K[Au(CN)2] + KOH
From the equation, we can see that 2 moles of KCN react with 1 mole of gold.
Step 3: Calculate the minimum amount of KCN needed.
Number of moles of KCN = 2 moles KCN / 1 mole Au * 0.1472 moles Au
= 0.2944 moles KCN
Therefore, the minimum amount of KCN in moles needed to extract 29 grams of gold is approximately 0.2944 moles.
To find the minimum amount of KCN in moles needed to extract gold, we need to use the molar mass of gold and the balanced chemical equation for the extraction reaction.
First, we determine the molar mass of gold (Au) using the periodic table. Gold has a molar mass of approximately 197 g/mol.
Next, we need to know the balanced chemical equation for the extraction of gold using KCN. The reaction is:
2Au + 4KCN + O2 + H2O → 2KAu(CN)2 + 2KOH
From the balanced equation, we can see that it takes 4 moles of KCN to extract 2 moles of gold.
Now, we can calculate the moles of gold in 29 grams. Using the formula:
moles = mass / molar mass
moles of gold = 29 g / 197 g/mol ≈ 0.147 moles (rounded to 3 decimal places)
Since it takes 4 moles of KCN to extract 2 moles of gold, we need to double the moles of gold to determine the moles of KCN required.
moles of KCN = 2 * moles of gold = 2 * 0.147 moles = 0.294 moles
Therefore, the minimum amount of KCN needed to extract 29 grams of gold is approximately 0.294 moles.