The answer is [Boron]
I had this answer on my Chemistry test!
Determine the number of moles in 258.45 grams of iron (III) chloride (FeCl3). Show and explain all
1 answer:
Answer:
Explanation:
To convert from grams to moles, we must use the molar mass. This can be found on the Periodic Table. First, find the molar mass of iron and chlorine.
- Fe: 55.84 g/mol
- Cl: 35.45 g/mol
Check the formula. There is a subscript of 3 after Cl, so there are 3 atoms of chlorine in 1 molecule. Multiply iron's molar mass by 3, then add iron's molar mass.
- FeCl₃: 55.84 + 3(35.45) = 55.84+106.35=162.19 g/mol
Use this number as a ratio.
Multiply by the given number of grams.
Flip the ratio so the grams of iron (III) chloride cancel.
The original measurement of grams has 5 significant figures, so our answer must have the same. For the number we calculated, that is the ten thousandth place.
258.45 grams is approximately 1.5935 moles of iron (III) chloride.
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Answer:
7.5 g
Explanation:
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<em>Ammonium phosphate ((NH₄)₃PO₄) is an important ingredient in many fertilizers. It can be made by reacting phosphoric acid (H₃PO₄) with ammonia (NH₃). What mass of ammonium phosphate is produced by the reaction of 4.9 g of phosphoric acid? Be sure your answer has the correct number of significant digits.</em>
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Step 1: Write the balanced equation
H₃PO₄ + 3 NH₃ ⇒ (NH₄)₃PO₄
Step 2: Calculate the moles corresponding to 4.9 g of phosphoric acid
The molar mass of phosphoric acid is 98.00 g/mol.
Step 3: Calculate the moles of ammonium phosphate produced from 0.050 moles of phosphoric acid
The molar ratio of H₃PO₄ to (NH₄)₃PO₄ is 1:1. The moles of (NH₄)₃PO₄ produced are 1/1 × 0.050 mol = 0.050 mol.
Step 4: Calculate the mass corresponding to 0.050 moles of ammonium phosphate
The molar mass of ammonium phosphate is 149.09 g/mol.