Answer:
d. 97.60 g
Explanation:
Given parameters:
Number of moles of formaldehyde = 3.25moles
Ratio:
C H O
1 2 1
Unknown:
Mass of this sample = ?
Solution:
The empirical formula of a compound is its simplest formula. It is the simplest whole number ratio of the atoms in a given substance.
The molecular formula is the actual formula of the compound.
Since the molecular and empirical formula are the same here, the formula of the compound is;
CH₂O
To find the mass of the formaldehyde, use the expression below;
Mass = number of moles x molar mass
molar mass of CH₂O = 12 + 2(1) + 16 = 30g/mol
Mass = 3.25 x 30 = 97.5g
The reaction that should be followed is
Na2SO4 + C<span>a(NO3)2 --> CaSO4 + 2NaNO3</span>
first calculate the limiting reactant
mol Na2SO4 = 0.075 L (<span>1.54×10−2 mol / L) = 1.155x10-3 mol
mol Ca(NO3)2 = 0.075 L (</span><span>1.22×10−2 mol / L) = 9.15x10-4 mol
so the limiting reactant is the Ca(NO3)2
so all of the Ca2+ will be precipitated, percentage unprecipitated = 0.00 % </span>
Answer:
False.
Explanation:
Scientific theories and hypothesis are all tentative. Science tries to prove something is either true of false and come up with answers (as much as we can) for many problems. Sometimes they are made based on limited data or information. Over the years, we come up with need findings discoveries which are able to give us more information and give us better answers. There have been a couple of scientific laws which had to be completely revised or discarded after new observations. An example of this would be the Laws of Thermodynamics. A couple of the laws have been changed over the decades after scientists made new disoveries and observations.
The mass in grams of each of the following using dimensional analysis is:
- 6.02 x 10²³ atoms of Mg = 12g of Mg
- 3.01 x 10²³ formula units of CaCl2 = 55.5g of CaCl2
- 12.4 x 10¹⁵ molecules of formaldehyde (CH2O) = 0.000000618g of formaldehyde
<h3>How to calculate mass?</h3>
The mass of a substance can be calculated in different ways depending on whether molecules or moles are given.
First, we need to convert atoms/formula units/molecules to moles as follows:
- 6.02 × 10²³ ÷ 6.02 × 10²³ = 1 mole of Mg
- 3.01 x 10²³ ÷ 6.02 × 10²³ = 0.5 moles of CaCl2
- 12.4 x 10¹⁵ ÷ 6.02 × 10²³ = 2.06 × 10-⁸ moles of formaldehyde
Next, we convert each mole value to mass as follows:
- 1 mole of Mg = 1 × 12 = 12g of Mg
- 0.5 moles of CaCl2 = 0.5 × 111 = 55.5g of CaCl2
- 2.06 × 10-⁸ moles of CH2O = 0.000000618g of formaldehyde
Learn more about mass at: brainly.com/question/19694949
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