Best meme wins brainlyest

Kryger [21]

Answer: B) Bones

Explanation:

Natural casts form when flowing water removes all of the original bone or tissue, leaving just an impression in sediment.

5 0

4 years ago

The bond between which two atoms is most polar

otez555 [7]

Answer:

bond

Explanation:

It is a polar bond because it is when two atoms bond

4 0

3 years ago

What activity occurs in the process of photosynthesis

Vaselesa [24]

Answer:

<h2>Photosynthesis is the process in which light energy is converted into chemical energy in the form of sugars. In a process powered by light energy, glucose (and other sugars) molecules are created from water and carbon dioxide, while oxygen is released as a by-product.</h2>

Explanation:

i'm mexican

4 0

3 years ago

How many liters of 0.615 M NaOH will be needed to raise the pH of 0.385 L of 5.13 M sulfurous acid (H2SO3) to a pH of 6.247?

givi [52]

Answer:

Volume of NaOH required = 3.61 L

Explanation:

H2SO3 is a diprotic acid i.e. it will have two dissociation constants given as follows:

$H2SO3\leftrightarrow H^{+}+HSO3^{-}$ --------(1)

where, Ka1 = 1.5 x 10–2 or pKa1 = 1.824

$HSO3^{-}\leftrightarrow H^{+}+SO3^{2-}$ --------(2)

where, Ka2 = 1.0 x 10–7 or pKa2 = 7.000

The required pH = 6.247 which is beyond the first equivalence point but within the second equivalence point.

Step 1:

Based on equation(1), at the first eq point:

moles of H2SO3 = moles of NaOH

$i.e. \ 5.13\ moles/L*0.385L = moles\ NaOH\\therefore, \ moles\ NaOH = 1.98\ moles\\V(NaOH)\ required = \frac{1.98\ moles}{0.615\ moles/L} =3.22L$

Step 2:

For the second equivalence point setup an ICE table:

$HSO3^{-}+OH^{-}\leftrightarrow H2O+SO3^{2-}$

Initial 1.98 ? 0

Change -x -x x

Equil 1.98-x ?-x x

Here, ?-x =0 i.e. amount of OH- = x

Based on the Henderson buffer equation:

$pH = pKa2 + log\frac{[SO3]^{2-} }{[HSO3]^{-} } \\6.247 = 7.00 + log\frac{x}{(1.98-x)} \\x=0.634 moles$

Volume of NaOH required is:

$\frac{0.634\ moles}{0.615 moles/L}=0.389L$

Step 3:

Total volume of NaOH required = 3.22+0.389 =3.61 L

3 0

3 years ago

a certain anesthetic contains 64.9% C, 13.5% H, and 21.6% O by mass. at 120 deg Celsius & 750 mmHg, 1.00 L of the gaseous co

slamgirl [31]

You need to use the % information to determine the empirical formula of the compound first.

The empirical formula is the simplest ratio of atoms in the molecule.

Then use the rest of the data to determine moles of gas, and use this to determine molar mass of gas...

Empirical formula calculations:

Assume you have 100 g, calculate the moles of each atom in the 100 g

moles = mass / molar mass
molar mass C = 12.01 g/mol
molar mass H = 1.008 g/mol
molar mass O = 16.00 g/mol

C = 64.9 % = 64.6 g
H = 13.5 % = 13.5 g
O = 21.6 % = 21.6 g

moles C = 64.6 g / 12.01 g/mol = 5.38 mol
moles H = 13.5 g / 1.008 g/mol = 13.39 mol
moles O = 21.6 g / 16.00 g/mol = 1.35 mol

So ratio of C : H : O
is 5.38 mol : 13.39 mol : 1.35 mol

Divide each number in the ratio by the lowest number to get the simplest whole number ratio

(5.38 / 1.35) : (13.39 / 1.35) : (1.35 / 1.35)

4 : 10 : 1

empirical formula is
C4H10O

Finding moles and molar mass calcs

Now, you know that at 120 deg C and 750 mmHg that 1.00L compound weighs 2.30 g.

We can use this information to determine the molar mass of the gas after first working out how many moles the are in the 1.00 L

PV = nRT
P = pressure = 750 mmHg
V = volume = 1.00 L
n = moles (unknown)
T = temp in Kelvin (120 deg C = (273.15 + 120) Kelvin)
- T = 393.15 Kelvin
R = gas constant, which is 62.363 mmHg L K^-1 mol^-1 (when your P is in mmHg and volume is in L)

n = PV / RT
n = (750 mmHg x 1.00 L) / (62.363mmHg L K^-1 mol^-1 x 393.15 K)
n = 0.03059 moles of gas

We know moles = 0.03509 and mass = 2.30 g
So we can work out molar mass of the gas

moles = mass / molar mass
Therefore molar mass = mass / moles
molar mass = 2.30 g / 0.03059 mol
= 75.19 g/mol

Determine molecular formula

So empirical formula is C4H10O
molar mass = 75.19 g/mol

To find the molecular formula you divide the molar mass by the formula weight of the empirical formula...
This tells you how many times the empirical formula fits into the molecular formula. Tou then multiply every atom in the empirical formula by this number

formula weight C4H10O = 74.12 g/mol

Divide molar mass by formula weight empirical
75.15 g/mol / 74.12 g/mol
= 1
(It doesn't matter that the number don't quite match, they rarely do in this type of calc (although I could have made a slight error somewhere) but the numbers are very close, so we can say 1.)

The empirical formula only fits into the molar mass once,

molecular formula thus = empirical formula

C4H10O

Therefore, the molecular formula of the compound is C4H10O.

I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!

5 0

3 years ago