Signs that a chemical reaction is occurring are: 1. change in color 2. change in odor 3. change in pH, as in changes from acid to base or base to acid
-Photons are absorbed by hot gas atoms
-Energy is transferred through large-scale movement of material
-Energy is released into the photosphere
This doesn't need an ICE chart. Both will fully dissociate in water.
Assume HClO4 and KOH reacts with one another. All you need to do is determine how much HClO4 will remain after the reaction. Calculate pH.
Step 1:
write out balanced equation for the reaction
HClO4+KOH ⇔ KClO4 + H2O
the ratio of HClO4 to KOH is going to be 1:1. Each mole of KOH we add will fully react with 1 mole of HClO4
Step 2:
Determining the number of moles present in HClO4 and KOH
Use the molar concentration and the volume for each:
25 mL of 0.723 M HClO4
Covert volume from mL into L:
25 mL * 1L/1000mL = 0.025 L
Remember:
M = moles/L so we have 0.025 L of 0.723 moles/L HClO4
Multiply the volume in L by the molar concentration to get:
0.025L x 0.723mol/L = 0.0181 moles HClO4.
Add 66.2 mL KOH with conc.=0.273M
66.2mL*1L/1000mL = .0662 L
.0662L x 0.273mol/L = 0.0181 moles KOH
Step 3:
Determine how much HClO4 remains after reacting with the KOH.
Since both reactants fully dissociate and are used in a 1:1 ratio, we just subtract the number of moles of KOH from the number of moles of HClO4:
moles HClO4 = 0.0181; moles KOH = 0.0181, so 0.0181-0.0181 = 0
This means all of the HClO4 is used up in the reaction.
If all of the acid is fully reacted with the base, the pH will be neutral = 7.
Determine the H3O+ concentration:
pH = -log[H3O+]; [H3O+] = 10-pH = 10-7
The correct answer is 1.0x10-7.
Answer:
Explanation:dndndbsnsjsjjsjsjssjjsjssjzjzjzjzjjxjxjx
<u>Plum Pudding Model(Thomson's atomic model)</u>
- Thomson's atomic model states that an atom has a positive sphere charge with electrons embedded inside it. He compared the atom with a plum pudding,as the electrons according to him seemed like the dry fruits embedded in the spherical pudding.
<u>Rutherford's Model</u>
- However Rutherford bombarded high energy streams of α-particles on a thin gold foil of 100 nm thickness. The deflection produced by the trajectory of these high energy α-particles after interaction with the thin sheet of gold was studied by placing a screen made up of zinc sulfide around the gold foil.
- The major observations made by Rutherford were that a very huge fraction of α-particles passed through the gold sheet without getting deflected. Thus he concluded that the major part of an atom must be empty.
- Very few α-particles got deflected minutely or at very small angles by the gold sheet when they were bombarded against it. Also very few particles got deflected at large angles. This made him conclude that the positive charge is concentrated in a very small region and is not distributed uniformly.
From the above observations he gave the following postulates:
- An atom is made up of positively charged particles. The mass of an atom was concentrated in small region which is named as the nucleus of an atom.
- The nucleus is surrounded by electrons which are negatively charged particles which revolve around the nucleus in a fixed circular path called as “orbits.”
- An atom is electrically neutral because electrons are negatively charged and the nucleus is positively charged. The electrons are held by the nucleus due to a strong electrostatic force.
- Compared to the total size of an atom the size of the nucleus is very small.
