What is another name for a mole?

Which of the following instrument would you use to see a plant cell?

Gemiola [76]

B . microscope
this is the answer .

3 0

2 years ago

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Determine the hydrogen ion concentration of solution B. [1]

bazaltina [42]

The hydrogen Ion concentration of solution B is
1.0 x 10^-5 or 0.000 010 M

You can see that this will be proportional to the amount of B's PH compared to A's

hope this helps

8 0

3 years ago

The acid-dissociation constant for benzoic acid (C6H5COOH) is 6.3×10−5. Calculate the equilibrium concentration of H3O+ in the s

raketka [301]

Answer : The equilibrium concentration of $H_3O^+$ in the solution is, $2.1\times 10^{-3}M$

Explanation :

The dissociation of acid reaction is:

$C_6H_5COOH+H_2O\rightarrow H_3O^++C_6H_5COO^-$

Initial conc. c 0 0

At eqm. c-x x x

Given:

c = $7.0\times 10^{-2}M$

$K_a=6.3\times 10^{-5}$

The expression of dissociation constant of acid is:

$K_a=\frac{[H_3O^+][C_6H_5COO^-]}{[C_6H_5COOH]}$

$K_a=\frac{(x)\times (x)}{(c-x)}$

Now put all the given values in this expression, we get:

$6.3\times 10^{-5}=\frac{(x)\times (x)}{[(7.0\times 10^{-2})-x]}$

$x=2.1\times 10^{-3}M$

Thus, the equilibrium concentration of $H_3O^+$ in the solution is, $2.1\times 10^{-3}M$

4 0

3 years ago

Identify each statement as true or false. Explain in every case.a.Ionization energies are always negative quantities.b.Oxygen ha

worty [1.4K]

Answer:

(a) FALSE

(b) FALSE

(c) TRUE

(d) FALSE

Explanation:

Ionization energy refers to the energy needed for removal of a valence electron present in valence shell of a gaseous atom.

(a) The value of ionization energy of an atom is always positive. This is because energy has to be always supplied or provided to a gaseous atom for the removal of the valence electron.

Therefore, the statement (A) is false

(b) The ionization energy of an atom increases across a period i.e. from left to right. This is because the effective nuclear charge that is experienced by the valence electron increases from left to right in the periodic table, as the atomic number increases.

So, more energy is required to remove the valence electron of fluorine as compared to oxygen.

Therefore, the ionization energy of fluorine is greater than oxygen.

Therefore, the statement (B) is false

(c) First ionization energy is energy needed for removal of first electron present in valence shell of a neutral atom. Whereas, second ionization energy is the energy needed for removal of second electron present in valence shell of a monovalent cation

The second ionization energy of an atom is always greater than the first ionization energy. This is because removing an electron from a positively charged species, requires more energy.

Therefore, the statement (C) is true

(d) The third ionization energy refers to the energy needed to remove the third electron from a divalent cation.

Therefore, the statement (D) is false

7 0

3 years ago

A 6.50x10^-5 m solution of potassium permanganate has a percent transmittance of 27.3% when measured in a 1.15 cm cell at a wave

mihalych1998 [28]

For this problem, we use the Beer Lambert's Law. Its usual equation is:

A = ∈LC
where
A is the absorbance
∈ is the molar absorptivity
L is the path length
C is the concentration of the sample solution

As you notice, we only have to find the absorbance. But since we are not given with the molar absorptivity, we will have to use the modified equation that relates % transmittance to absorbance:

A = 2 - log(%T)
A = 2 - log(27.3)
A = 0.5638

7 0

3 years ago