Answer:
The atomic weight of Rubidium (Rb) is 85.91 amu, using 4 significant figures.
Explanation:
The average atomic mass of Rubidium (Rb) is composed by the mass of the two given isotopes 85^Rb and 87^Rb but each isotope has a different abundance in nature expressed by percentage (natural occurrence).
Therefore, we need to calculate how much of this mass with its abundance percentage contribute to the average atomic mass for each isotope.
First step: Calculate the contribution in mass using the natural occurrence percentage.
85^Rb = 84.91 × 
= 61.73 amu
87^Rb = 86.91 ×
= 24.18 amu
The answers for each isotope are given using a typical percentage formula.
Second step: Add the two mass values founded.
24.18 amu + 61.73 amu = 85.91 amu
Third Step: Check the significant figures
The answer is 85.91 amu and it has 4 significant figures.
All the layers should be kept until the experiment is complete.
<h3>What is extraction?</h3>
In chemistry, solvent extraction is accomplished by adding a sample containing the substance to be separated into a system of two solvents, an aqueous layer and an organic layer.
It is important to note that all the layers should be kept until the experiment is complete. No layer ought to be discarded before the work is completed.
Learn more about solvent extraction:brainly.com/question/11041092
Answer:
The reaction isn't yet at equilibrium. The overall reaction will continue to move in the direction of the products.
Assumption: this system is currently at 
.
Explanation:
One way to tell whether a system is at its equilibrium is to compare its reaction quotient 
with the equilibrium constant 
of the reaction.
The equation for is quite similar to that for . The difference between the two is that requires equilibrium concentrations, while can be calculated even when the system is on its way to equilibrium.
For this reaction,
![\displaystyle Q = \rm \frac{[CS_2]\cdot [H_2]^{4}}{[CH_4]\cdot [H_2S]^{2}}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20Q%20%3D%20%5Crm%20%5Cfrac%7B%5BCS_2%5D%5Ccdot%20%5BH_2%5D%5E%7B4%7D%7D%7B%5BCH_4%5D%5Ccdot%20%5BH_2S%5D%5E%7B2%7D%7D)
.
Given these concentrations,
![\displaystyle Q = \rm \frac{[CS_2]\cdot [H_2]^{4}}{[CH_4]\cdot [H_2S]^{2}} =\frac{1.51\times (1.08)^{4}}{1.15\times (1.20)^{2}} \approx 1.72](https://tex.z-dn.net/?f=%5Cdisplaystyle%20Q%20%3D%20%5Crm%20%5Cfrac%7B%5BCS_2%5D%5Ccdot%20%5BH_2%5D%5E%7B4%7D%7D%7B%5BCH_4%5D%5Ccdot%20%5BH_2S%5D%5E%7B2%7D%7D%20%3D%5Cfrac%7B1.51%5Ctimes%20%281.08%29%5E%7B4%7D%7D%7B1.15%5Ctimes%20%281.20%29%5E%7B2%7D%7D%20%5Capprox%201.72)
.
The question states that at , 
. Assume that currently this system is also at . (The two temperatures need to be the same since the value of depends on the temperature.)
It turns out that 
. What does this mean?
- First, the system isn't at equilibrium.
- Second, if there's no external changes, the system will continue to move towards the equilibrium. Temperature might change. However, eventually will be equal to , and the system will achieve equilibrium.
In which direction will the system move? At this moment, 
. As time proceeds, the value of will increase so that it could become equal to . Recall that is fraction.
When the value of increases, either its numerator becomes larger or its denominator becomes smaller, or both will happen at the same time. However,
- Concentrations on the numerator of are those of the products;
- Concentrations on the denominator of are those of the reactants.
As time proceeds,
- the concentration of the products will increase, while
- the concentration of the reactants will decrease.
In other words, the equilibrium will move towards the products.
Answer: It is a helium nuclei.
Explanation: Alpha particles are produced when a larger nuclei decays into smaller nuclei in radioactive decay. Alpha particles have mass number and atomic number as 4 and 2 respectively.
General representation of alpha decay :
A physical process is a process which do not change the substance structure only its shape or phase is changed. On the other hand, a chemical process involves the formation of new substances.
a. corrosion of aluminum metal = chemical process
b. Melting of ice = physical process
c. Pulverizing an aspirin. = physical processd. Digesting a candy bar. = chemical process
e. Explosion of nitroglycerin. = chemical process
f. Milk turning sour. = chemical process
g. Burning of paper. = chemical process
h. Forming of frost on a cold night. = physical process
i. Bleaching of hair with hydrogen peroxide. = chemical process
j. A copper wire is hammered flat. <span>= physical process</span>
