Answer:
A piece of gold foil was hit with alpha particles, which have a positive charge. Most alpha particles went right through. This showed that the gold atoms were mostly empty space. Some particles had their paths bent at large angles. A few even bounced backward. The only way this would happen was if the atom had a small, heavy region of positive charge inside it.
Answer is: <span>D. Tin atoms give electrons to lead(II) ions and are oxidized to tin(II) ions.
Chemical reaction: Sn</span>⁰ + Pb²⁺ → Sn²⁺ + Pb.
Tin atom (oxidation number 0) give two electrons to led ions, oxidation number of tin is greater now (oxidation number +2).
<span>Oxidation is loss of electrons.</span>
Answer:
Pressure
Explanation:
They are both equal but do not change when the other does
Answer:
A. A line graph
Explanation:
You use line graphs to track changes over time. Line graphs are better when the changes are small. They are also more useful when you want to compare changes over the same period for more than one group, for example, plants exposed to music and a control group.
B is wrong. A pie chart is best for comparing parts of a whole.
C is wrong. You can use a bar graph to track changes over time, but small changes are harder to spot.
D is wrong. You use a timeline to mark important points in time, for example, when you are deciding the times when you must complete various stages of a project.
Which of the charts below do you think is more helpful in showing the change in plant height over time?
Answer:
Dissociated state is the predominant one
Explanation:
When a molecule with pKa of 4.52 is in an aqueous solution at pH = 4.0, follows the H-H equation, thus:
pH = pKa + log₁₀ [A⁻] / [HA]
<em>Where [A⁻] is the dissociated state and [HA] represents the protonated state</em>
Replacing:
4.0 = 5.2 + log₁₀ [A⁻] / [HA]
-1.2 = log₁₀ [A⁻] / [HA]
0.063 = [A⁻] / [HA]
[HA] = 16 [A⁻]
That means you have 16 times more [HA] than [A⁻] and the <em>dissociated state is the predominant one</em>
