Answer:
II and IV.
Explanation:
I. (INCORRECT). A model is a tentative to determinate a thing that can't be proved, and it's made based on evidence. If the model can explain the observation in nature, it is considered right, although it can be proved by a theory.
II. (CORRECT). The most accepted model of atoms says that they're formed by tiny particles, protons, neutrons, and electrons, with the first two on the nucleus, and the other surrounding it in an open space.
III. (INCORRECT). A heterogeneous mixture is a mixture of substances that is possible to identify phases of them, such as in oil and water. In the air, isn't possible to identify the constituents, and it's a homogeneous mixture.
IV. (CORRECT). Silver has atomic number 47, which is its number of protons. The atomic mass is the sum of protons and neutrons, so the number of neutrons is 108 - 47 = 61.
Explanation:
Given parameters:
Number of moles of the sulfur trioxide = 1.55kmol = 1.55 x 10³mole
Unknown:
Mass of the sulfur trioxide = ?
Solution:
To solve for the mass of the sample of sulfur trioxide:
- Find the molar mass of the compound i.e SO₃
atomic mass of S = 32g
O = 16g
molar mass = 32 + 3(16) = 80g/mol
mass of SO₃ = number of moles x molar mass
mass of SO₃ = 1.55 x 10³ x 80 = 124000g or 124kg
Learn more:
mole calculation brainly.com/question/13064292
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Answer:
The heat of vaporization describes how much energy is needed to separate these bonds. Water has a high heat of vaporization because hydrogen bonds form readily between the oxygen of one molecule and the hydrogens of other molecules. These bonds hold the molecules together.
Explanation:
The correct answer would be B for sure
