Scientific models _______. a. are based on a set of observations b. are used to replace experiments c. allow the study of existi
2 answers:
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Answer:
1.25mole of Mg(OH)₂
Explanation:
The reaction is between Mg(OH)₂ and HCl, this is a neutralization reaction between an acid and a base.
Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O
The balanced reaction equation is given above.
2 mole of HCl reacts with 1 mole of Mg(OH)₂
So, 2.5mole of HCl will react with = 1.25mole of Mg(OH)₂
The number of moles of Mg(OH)₂ is given as 1.25mol
Answer:
Explanation:
First, we need to find the molecular mass of water (H₂O).
H₂O has:
- 2 Hydrogen atoms (subscript of 2)
- 1 Oxygen atom (implied subscript of 1)
Use the Periodic Table to find the mass of hydrogen and oxygen. Then, multiply by the number of atoms of the element.
- Hydrogen: 1.0079 g/mol
- Oxygen: 15.9994 g/mol
There are 2 hydrogen atoms, so multiply the mass by 2.
- 2 Hydrogen: (1.0079 g/mol)(2)= 2.0158 g/mol
Now, find the mass of H₂O. Add the mass of 2 hydrogen atoms and 1 oxygen atom.
- 2.0158 g/mol + 15.9994 g/mol = 18.0152 g/mol
Next, find the amount of moles using the molecular mass we just calculated. Set up a ratio.
Multiply. The grams of H₂O will cancel out.
The original measurement given had two significant figures (3,2). We must round to have 2 significant figures. All the zeroes before the 1 are not significant. So, round to the ten thousandth.
The 7 in the hundred thousandth place tells us to round up.
There are about <u>0.0018 moles in 0.032 grams.</u>