Explanation:
The observation of student was that thermometer reading changed from 27°C to 35°C which indicates that temperature of the beaker solution rose after reaction due to release of heat during reaction as a product.
Those chemical reactions which gives heat energy as a product into their surrounding are categorized as exothermic reactions. During the course of these reaction temperature of the surroundings also increased.
So, this means that reaction between silver nitrate and copper wire is an exothermic reaction.
Three ways that the student could speed up the reaction :
- By adding catalyst to the reaction.
- By decreasing the temperature.
- By increasing the concentration of silver nitarte solution.
An acidic solution is 0.1M in HCl and 0.2 H2so4. volume is equal to no of moles divided by molarity.
number of moles of HCl is 450ml x 0.1 divided by 1000 which is equal to 0.045 moles
volume of HCl is therefore 0.45 divided by 0.16 which is 2.81 litres
Number of moles of H2so4 is 450ml x 0.2 divided by 1000 which is equal to 0.09 moles
volume of H2SO4 IS 0.09 divided by 0.16 which is equal to 0.56 litres
Answer:
A = 679.2955 ppm
Explanation:
In this case, we already know that 64Cu has a half life of 12.7 hours. The expression to use to calculate the remaining solution is:
A = A₀ e^-kt
This is the expression to use. We have time, A₀, but we do not have k. This value is calculated with the following expression:
k = ln2 / t₁/₂
Replacing the given data we have:
k = ln2 / 12.7
k = 0.0546
Now, let's get the concentration of Cu:
A = 845 e^(-0.0546*4)
A = 845 e^(-0.2183)
A = 845 * 0.8039
A = 679.2955 ppm
This would be the concentration after 4 hours
The location of the valence electron or the outermost electron is expressed in quantum numbers. There are five quantum numbers: prinicipal (n), angular momentum (l), magnetic (ms) and magnetic spin (ms) quantum numbers. This is based on Bohr's atomic model where electrons orbit around the nucleus. These electrons are in the orbitals with specific energy levels. Starting from energy level 1 that is closest to the nucleus, the energy level decreases to 2, 3, 4, 5, 6, and 7. These energy level numbers represent the principal quantum number. Within each orbital also contains subshell. From increasing to decreasing order, these subshells are the s, p, d and f subshells. These subshells represent the angular momentum quantum numer. Specifically, s=0, p=1, d=2 and f=3. Therefore, if the electron is in the orbital 5p, the quantum number would be: 5, 1. Applying these to the choices, the correct pairing would be:
2p: n=2. l=1
3d: n=3, l=2
2s: n=2. l=0
4f: n=4. l=3
1s: n=1, l=0
