Metamorphic rocks that melt in a hot fluid can re-crystallize into a different form of rock. true or false

If the ph of hc3h5o2 is 4.2 and the ka 1.34x10^-5, what is the equilibrium concentration

n200080 [17]

CH₃CH₂COOH + H₂O ↔ CH₃CH₂COO⁻ + H₃O⁺

pH = 0.5 pKa + 0.5 pCa
0.5 pCa = pH - 0.5 pKa
= 4.2 - (0.5 * (-log 1.34 x 10⁻⁵)) = 1.76
pCa = 3.53
Ca = antilog - 3.52 = 3 x 10⁻⁴
where Ca is the acid concentration

5 0

3 years ago

An individual with the disorder Xeroderma pigmentosum is hypersensitive to sunlight succumbs to DNA damage caused by light expos

olya-2409 [2.1K]

This disorder is inherited through DNA because there is a lack of pigmentation in the skin.

6 0

3 years ago

An element has five isotopes. Calculate the atomic mass of this element using the information below. Show all your work. Using t

Katena32 [7]

Answer: Sol:-

Data provided in the question is :-

Atomic mass of isotope -1 = 64 amu

Atomic mass of isotope -2 = 66 amu

Atomic mass of isotope -3 = 67 amu

Atomic mass of isotope -4 = 68 amu

Atomic mass of isotope - 5 = 70 amu

Percentage abundace of isotope - 1 = 48.89 %

Percentage abundance of isotope -2 = 27.81 %

Percentage abundance of isotope - 3 = 4.11%

Percentage abundance of isotope-4 = 18.57%

Percentage abundance of isotope - 5 = 0.62 %

Formula used :-

Average atomic mass of an element =[ {(atomic mass of isotope-1 * percentage abundance of isotope-1) + ( atomic mass of isotope-2 * percentage abundance of isotope -2) + ( atomic mass of isotope -3 * percantege abundance of isotope-3 ) + ( atomic mass of isotope-4 * percentage abundance of isotope-4) + (atomic mass of isotope-5 * percentage abundance of isotope-5)} / 100]

Calculation :-

Put all the value in the formula :-

Average atomic mass of an element = [{(64 * 48.89) + (66 * 27.81) + (67 * 4.11) + (68 * 18.57) + (70 * 0.62)} / 100] amu

= [{(3128.96) + (1835.46) +(257.37) + (1262.76) + (43.4)} / 100] amu

= {(6528.04) / 100} amu

= 65.2804 amu

Average atomic mass of an element is = 65.2804 amu

Then this mass is approximatly equal to atomic mass of zinc so this element would be zinc

atomic mass of zinc = 65.38 \approx 65.2804 amu

5 0

3 years ago

Lily is doing a science experiment with a substance in a sealed jar. At first, the substance's molecules are moving around each

Alex

The molecules will be more separated, and will have least amount of intermolecular force of attraction.

<h3>Explanation:</h3>

The molecules inside the jar of Lilly are moving around each other. This means the state of the matter present inside the jar is liquid. As Lily gives more energy inside the jar , the molecules inside the jar will get more separated as the kinetic energy of the molecules increase and the intermolecular force of attraction decreases as well as the intermolecular separation or distance increase. As the energy is continued to be supplied from outside, there will be a time when this liquid will reaches boiling point and will start to change into gas. After this point the intermolecular force of attraction will be least among molecules and their separation will be maximum.

6 0

3 years ago

The shape of the BF3 molecule is best described as

Mars2501 [29]

Answer:

The shape of the BF3 molecule is best described as trigonal planar.

Explanation:

The Lewis Structure for BF3 is like this:

_ _

| F | | F |

\ /

B

|

| F |

---

It forms three angles of 120° each. The bonds are in the same planar that's why it is trigonal planar and they are exactly the same.

Boron and Fluorine have 3 covalent bonds, produced by electronic promotion that enables the 2py and 2pz orbitals, leaving an electron to pair in the 2px. So boron will have 3 possible electrons to pair in 2s1, 2px and 2py, remember that electronic configuration for B is 1s2, 2s2, 2p1

By hybridization between the orbitals 2s2 and 2p1, the electrons of F, can joined to make the covalent bond. The new B configuration is 1s2, 2s1, 2px1, 2py1 (these last three, hybrid orbitals)

5 0

3 years ago