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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Answer: Rate of decomposition of acetaldehyde in a solution is 
Explanation:
Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.
For a reaction : 
![Rate=k[A]^x](https://tex.z-dn.net/?f=Rate%3Dk%5BA%5D%5Ex)
k= rate constant
x = order of the reaction = 2


Thus rate of decomposition of acetaldehyde in a solution is
Answer:
Explanation:
2S + 3O₂ = 2SO₃
2moles 3 moles
2 moles of S react with 3 moles of O₂
5 moles of S will react with 3 x 5 / 2 moles of O₂
= 7.5 moles of O₂ .
O₂ remaining unreacted = 10 - 7.5 = 2.5 moles .
All the moles of S will exhausted in the reaction and 2.5 moles of oxygen will be left .
Answer:
The formula for volume of a rectangle is length multiply by width multiply thus, 0.25 m multiply 6.1 m multiply by 4.9 m = 7.5m^3.
Explanation:
the least number of significant figures is 2 thus the final answer will have the same number of significant figures. 7.5m^3
Hydrogen bonds are a strong attractive force, since they are less stronger than ionic bonds.