We are given the pOH of the solution of 10.75. pOH is the property of the solution that is related to the OH ion concentration of the solution. THe formula to be followed is pOH = -log (OH); OH- = 10^-pOH. In this case, OH- = 10^-10.75 equal to B. 1.778 x 10^-11 M
Answer:
Volume of the solutions
This is the most important factor for her to control.
The whitening toothpastes showed differences in their physical-chemical properties. All toothpastes promoted changes to the surface, probably by the use of a bleaching agent.
Answer:
3,964 years.
Explanation:
- It is known that the decay of a radioactive isotope isotope obeys first order kinetics.
- Half-life time is the time needed for the reactants to be in its half concentration.
- If reactant has initial concentration [A₀], after half-life time its concentration will be ([A₀]/2).
- Also, it is clear that in first order decay the half-life time is independent of the initial concentration.
- The half-life of the element is 5,730 years.
- For, first order reactions:
<em>k = ln(2)/(t1/2) = 0.693/(t1/2).</em>
Where, k is the rate constant of the reaction.
t1/2 is the half-life of the reaction.
∴ k =0.693/(t1/2) = 0.693/(5,730 years) = 1.21 x 10⁻⁴ year⁻¹.
- Also, we have the integral law of first order reaction:
<em>kt = ln([A₀]/[A]),</em>
where, k is the rate constant of the reaction (k = 1.21 x 10⁻⁴ year⁻¹).
t is the time of the reaction (t = ??? year).
[A₀] is the initial concentration of the sample ([A₀] = 100%).
[A] is the remaining concentration of the sample ([A] = 61.9%).
∴ t = (1/k) ln([A₀]/[A]) = (1/1.21 x 10⁻⁴ year⁻¹) ln(100%/61.9%) = 3,964 years.
Passive prostheses are self-regulating, as shown in the first answer option.
We can arrive at this answer because:
- Passive prostheses are devices used to replace parts of the body that were lost by an incident.
- These prostheses are very useful to establish balance or the aesthetics of the body, but they have no articulations and no movement mechanism, being static.
This limitation allows passive prostheses not to need external regulation and to be self-regulated by fitting the body parts.
You can find more information about articulations and their effects on the link:
brainly.com/question/5847359?referrer=searchResults
