If 2.5 g of element A combine with 5 g of element B to form compound AB how many grams of B are needed to form compound AB2? Which law did you use to answer this question ? My answer is 7.5 g. Im not sure if this is right. Please help this is due Thursday morning C an you please show me how to do it so I can do it next time teacher ask. I'm so confuse don't wanna give up. PLS ANSWER ILL WAIT. THANK YOU SO MUCH

Question

If 2.5 g of element A combine with 5 g of element B to form compound AB how many grams of B are needed to form compound AB2? Which law did you use to answer this question ? My answer is 7.5 g. Im not sure if this is right. Please help this is due Thursday morning C an you please show me how to do it so I can do it next time teacher ask. I'm so confuse don't wanna give up. PLS ANSWER ILL WAIT. THANK YOU SO MUCH

Answer 1

To determine the number of grams of element B needed to form compound AB2, you need to consider the ratio of the elements in the compounds.

Let's start by calculating the molar mass of both element A and element B. The molar mass can be found on the periodic table.

For example, let's assume that the molar mass of element A is 20 g/mol, and the molar mass of element B is 10 g/mol.

Step 1: Determine the number of moles of element A.
Given that the mass of element A is 2.5 g and the molar mass of A is 20 g/mol, you can calculate the number of moles using the formula:

moles of A = mass of A / molar mass of A

moles of A = 2.5 g / 20 g/mol = 0.125 mol

Step 2: Determine the number of moles of element B in relation to element A.
According to the given information, the ratio between element A and element B in compound AB is 1:2. This means that for every 1 mole of A, there are 2 moles of B.

Since the number of moles of A is 0.125 mol, we can calculate the number of moles of B using the ratio:

moles of B = moles of A * (2 moles of B / 1 mole of A)

moles of B = 0.125 mol * (2 mol B / 1 mol A) = 0.25 mol

Step 3: Convert moles of B to grams.
Now, we can convert the number of moles of B to grams using the molar mass of element B. In this case, the molar mass of B is 10 g/mol.

mass of B = moles of B * molar mass of B

mass of B = 0.25 mol * 10 g/mol = 2.5 g

Therefore, to form compound AB2, you would need 2.5 grams of element B.

The law used to answer this question is the Law of Definite Proportions, which states that a chemical compound always contains the same elements in fixed proportions by mass. In this case, the ratio of element B to element A is fixed, leading to a specific mass of B required to form the compound AB2.