Answer: caffeine is a compound.
Explanation:
1) As stated c<span>affeine contains hydrogen, carbon, nitrogen, and oxygen atoms in a fixed ratio.
2) The definition of compound is a pure substance formed by chemical bonding of two or more fifferent elements. That means a defined ratio of the elements in the compound, which conferes uniform and equal properties to every part of the compound.
Some examples of compounds are salt (NaCl), water (H2O), vinegard (CH3 COOH).
A mixture combines several elements or compounds, not bonded by chemical bonds but mixed in ratios which may vary.
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The photoelectric effect supports a particle theory of light in that it behaves like an elastic collision (one that conserves mechanical energy) between two particles, the photon of light and the electron of the metal.
I think 8, because you have to end up with a balanced equation.
Answer:
4.16x10⁻³m
Explanation:
Molality is defined as the ratio between moles of a solute, in this case glucose, and kg of solvent.
As there are 100g of solvent, <em>the kg are 0.1. </em>Thus, we only need to calculate from the mass of glucose its moles to solve the molality of the solution.
<em>Moles glucose:</em>
There are 75mg = 0.075g of glucose. To conver mass to moles it is necessary molar mass.
Molar mass glucose:
6C = 12.01g/mol*6 = 72.06g/mol
12H = 12*1.008g/mol = 12.10g/mol
6O = 6*16g/mol = 96g/mol
72.06 + 12.10 + 96 = 180.16g/mol
Moles of 0.075g of glucose:
0.075g * (1 mol / 180.16g) =
4.16x10⁻⁴ moles of glucose
<em>Molality of the solution:</em>
4.16x10⁻⁴ moles of glucose / 0.1kg of solvent =
<h3>4.16x10⁻³m</h3>
