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3 years ago

Select the correct answer from each drop-down menu.

Chemistry

1 answer:

Trava [24]3 years ago

3 0

Answer:

The answer is

1) Essential Fatty Acids

2) Cell Membrane

Explanation:

You might be interested in

Select the conjugate acid-base pair(s). a) HI, I b) HCHO2, SO4^2- c) CO3^2-, HCI d) PO4^3-, HPO4^2-

Semenov [28]

Answer:

d) PO4^3-, HPO4^2-

Explanation:

Basically, an acid and a base which differs only by the presence or absence of proton (hydrogen ion) are called a conjugate acid-base pair.

a) HI, I

This is incorrect. For the acid, HI the conjugate base is I⁻ ion.

b) HCHO2, SO4^2-

This is incorrect, there's no relationship between both entities.

c) CO3^2-, HCI

This is incorrect, there's no relationship between both entities.

d) PO4^3-, HPO4^2-

This is correct. The difference between both entities is the Hydrogen ion. This is the conjugate acid-base pair

6 0

3 years ago

What have all living things evolved from?

EastWind [94]

Answer:

Coprolites.........!!!

3 0

3 years ago

Read 2 more answers

What is the mole fraction, X, of solute and the molality, m (or b), for an aqueous solution that is 15.0% NaOH by mass?

GalinKa [24]

Hello!

a) The mole fraction of solute of a 15% NaOH aqueous solution can be calculated in the following way:

First, we have to assume that we have 100 grams of solution. This will simplify the calculations.

Now, we know that this solution has 15 grams of NaOH and 85 grams of water. We can calculate the number of moles of each one in the following way:

$molesNaOH= 15 g NaOH*\frac{1molNaOH}{39,997 g NaOH}=0,3750 moles NaOH \\ \\ moles H_2O=85 gH_2O* \frac{1 mol H_2O}{18 g H_2O}=4,7222 moles H_2O$

To finish, we calculate the mole fraction by dividing the moles of NaOH between the total moles:

$X_{NaOH}= \frac{moles NaOH}{total moles}= \frac{0,3750 moles NaOH}{0,3750 moles NaOH+4,7222 molesH_2O} =0,073$

So, the mole fraction of NaOH is 0,073

b) The molality (moles NaOH/ kg of solvent) of a 15% NaOH aqueous solution can be calculated in the following way:

First, we have to assume that we have 100 grams of solution. This will simplify the calculations.

Now, we know that this solution has 15 grams of NaOH and 85 grams (0,085 kg) of water. We can calculate the moles of NaOH in the following way:

$molesNaOH= 15 g NaOH*\frac{1molNaOH}{39,997 g NaOH}=0,3750 moles NaOH$

Now, we apply the definition of molality to calculate the molality of the solution:

$mNaOH= \frac{moles NaOH}{kg_{solvent}}= \frac{0,3750 moles NaOH}{0,085 kg H_2O}=4,41 m$

So, the molality of this solution is 4,41 m

Have a nice day!

4 0

3 years ago

A 4.000 g sample of an unknown metal, M, was completely burned in excess O2 to yield 0.02225 mol of the metal oxide, M2O3. What

Solnce55 [7]

4X + 3O₂ = 2X₂O₃

n(X₂O₃)=0.02225 mol
m(X)=4.000 g
x - the molar mass of metal

m(X)/4x=n(X₂O₃)/2

x=m(X)/{2n(X₂O₃)}

x=4.000/{2*0.02225)=89.89 g/mol

X=Y (yttrium)

7 0

3 years ago

4. Write the chemical formulas for the following compounds:

IRISSAK [1]

Lithium oxide ( Li2O)
Carbon monoxide ( CO )
Carbon tetrachloride ( CCl4 )
Nitrogen trifluoride ( NF3 )
Calcium chloride ( CaCl2)

4 0

2 years ago