Answer:
Option A: 1*10^-5 M HCl has a pH of 5
Explanation:
a) 1.0 * 10^‒5 M HCl
HCl = a strong acid
pH of HCl = -log[H+]
ph of a 10^‒5 M HCl = -log(10^-5) = 5
(b) 1.0 * 10^5 M NaOH
pOH = -log(10^-5) = 5
pH = 14 -5 = 9
(c) A solution containing approximately equal concentrations of hypochlorous acid (HOCl, Ka = 2.9 * 10^‒8) and the dissolved salt of its conjugate base sodium hypochlorite (NaOCl).
pH = pKa + log[NaOCl/HOCl]
Since [NaOCl]/ [HOCl]= 1
pH = pKa +log(1)
pH = pKa
pH = -log(2.9 * 10^-8)
pH = 7.54
(d) A solution containing approximately equal concentrations of potassium hydrogen phthalate (C8H5KO4, Ka = 3.91 * 10^–6) and the dissolved salt of its conjugate base potassium phthalate.
pH = pKa +log[potassium phthalate/C8H5KO4)
Since [potassium phthalate]/[C8H5KO4] = 1
pH = pKa
pH = -log(3.91*10^-6)
pH = 5.41
e) A solution containing approximately equal concentrations of ammonia (Kb = 1.8 * 10^‒5) and the dissolved salt of its conjugate acid ammonium chloride.
pOH = pKb +log[NH4Cl]/[NH3]
Since [NH4Cl]/[NH3] = 1
pOH = pKb
pOH = 4.74
pH = 14-4.74 = 9.26
The equation for density id D=M/V, which is density is equal to mass over volume. The mass (46.8 g) divided by the volume (6 cm^3), is the density. I calculated it to be 7.8 g/cm^3
Answer:
Yeast cell is different from an onion skin cell in that Yeast can reproduce by budding while onion skin cells do not reproduce by budding.
Explanation:
- Reproduction is one of the characteristics of living organisms. All living organisms undertake reproduction to give rise to new organisms.
- There are two major types of reproduction namely asexual and sexual reproduction.
- Asexual reproduction is a form of reproduction that does not involve the fusion of gametes among organisms. Examples of asexual reproduction are budding in yeast and vegetative propagation in plants such as onions.
- Sexual reproduction, on the other hand, involves the fusion of gametes from male and female organisms which results in the formation of an embryo that develops to the fetus which becomes the offspring.
- Therefore, we could say that yeast cells reproduce asexually through budding while onions reproduce asexually through vegetative propagation.
Answer:
f = V / λ
Explanation:
In this formula, f represents frequency, V represents the velocity of the wave, and λ represents the wavelength of the wave
Answer:
Avogadro’s Number
Avogadro’s NumberIt certainly is easy to count bananas or to count elephants (as long as you stay out of their way). However, you would be counting grains of sugar from your sugar canister for a long, long time. Atoms and molecules are extremely small – far, far smaller than grains of sugar. Counting atoms or molecules is not only unwise, it is absolutely impossible. One drop of water contains about 10 22 molecules of water. If you counted 10 molecules every second for 50 years without stopping you would have counted only 1.6 × 10 10 molecules. Put another way, at that counting rate, it would take you over 30 trillion years to count the water molecules in one tiny drop.
Avogadro’s NumberIt certainly is easy to count bananas or to count elephants (as long as you stay out of their way). However, you would be counting grains of sugar from your sugar canister for a long, long time. Atoms and molecules are extremely small – far, far smaller than grains of sugar. Counting atoms or molecules is not only unwise, it is absolutely impossible. One drop of water contains about 10 22 molecules of water. If you counted 10 molecules every second for 50 years without stopping you would have counted only 1.6 × 10 10 molecules. Put another way, at that counting rate, it would take you over 30 trillion years to count the water molecules in one tiny drop.Chemists needed a name that can stand for a very large number of items. Amedeo Avogadro (1776 – 1856), an Italian scientist, provided just such a number. He is responsible for the counting unit of measure called the mole. A mole (mol) is the amount of a substance that contains 6.02 × 10 23 representative particles of that substance. The mole is the SI unit for amount of a substance. Just like the dozen and the gross, it is a name that stands for a number. There are therefore 6.02 × 10 23 water molecules in a mole of water molecules. There also would be 6.02 × 10 23 bananas in a mole of bananas, if such a huge number of bananas ever existed