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3 years ago

Which of the following best describes a mixture? *

Chemistry

2 answers:

marin [14]3 years ago

8 0

I am pretty sure it is the first one. Since it is definitely not the second or last one.
Hope this helped!

luda_lava [24]3 years ago

7 0

Answer: two or more substances combine but keep their physical properties or two or more substances combine and create an irreversible reaction.

Explanation: Because i tried the other two and they didnt work so yeah thats life and i got a d on my test thx for the wrong info person before me.

You might be interested in

Which of the following characteristics do all unicellular organisms share?

Serhud [2]

Unicellular organisms...

Contain a single cell in their body

Do not contain membrane bound organelles

Use simple diffusion as a transport mechanism

All cellular processes are carried out by the single cell

Only visible under the microscope

Injury in the cell leads to the death of the organism

Asexually reproduce by binary fission

Sexually reproduce by conjugation

Lifespan is comparatively short

3 0

3 years ago

A buffer solution is made that is 0.347 M in H2C2O4 and 0.347 M KHC2O4.

irga5000 [103]

Answer:

1. pH = 1.23.

2. $H_2C_2O_4(aq) +OH^-(aq)\rightarrow HC_2O_4^-(aq)+H_2O(l)$

Explanation:

Hello!

1. In this case, for the ionization of H2C2O4, we can write:

$H_2C_2O_4\rightleftharpoons HC_2O_4^-+H^+$

It means, that if it is forming a buffer solution with its conjugate base in the form of KHC2O4, we can compute the pH based on the Henderson-Hasselbach equation:

$pH=pKa+log(\frac{[base]}{[acid]} )$

Whereas the pKa is:

$pKa=-log(Ka)=-log(5.90x10^{-2})=1.23$

The concentration of the base is 0.347 M and the concentration of the acid is 0.347 M as well, as seen on the statement; thus, the pH is:

$pH=1.23+log(\frac{0.347M}{0.347M} )\\\\pH=1.23+0\\\\pH=1.23$

2. Now, since the addition of KOH directly consumes 0.070 moles of acid, we can compute the remaining moles as follows:

$n_{acid}=0.347mol/L*1.00L=0.347mol\\\\n_{acid}^{remaining}=0.347mol-0.070mol=0.277mol$

It means that the acid remains in excess yet more base is yielded due to the effect of the OH ions provided by the KOH; therefore, the undergone chemical reaction is:

$H_2C_2O_4(aq) +OH^-(aq)\rightarrow HC_2O_4^-(aq)+H_2O(l)$

Which is also shown in net ionic notation.

Best regards!

4 0

3 years ago

How many g of MgCO3(s) are needed to make 1.2 L of 1.5 M MgCl2(aq) solution?

maw [93]

Molar mass of MgCO3 is 84.313 g/mol
You can calculate this from data on the periodic table:
Molar mass Mg = 24.305g/mol
molar mass C = 12.011g/mol
molar mass O = 15.999g/mol mass 3 mol = 47.997g
Total = 84.313g/mol

Mass to be used in 1.2L of 1.5M solution = 84.313g * 1.2L * 1.5mol /L = 151.763g
I have not taken significant figures into account
The balanced equation you provide is not necessary in this calculation

4 0

3 years ago

Match each term with its definition.

padilas [110]

Answer:

The position of an equilibrium always shifts in such a direction as to relieve a stress applied to the system -Le Chåtelier's principle

A molecule that donates a proton when it encounters a proton acceptor.- Bronsted-Lowry acid

Occurs when a reaction involving an acid and its conjugate base is combined with a second reaction involving a base and its conjugate acid.- Neutralization

It ionizes completely when dissolved in water.- Strong acid

The shift in the position of equilibrium caused by the addition of a participating ion.- Common ion effect

It only partially ionizes when dissolved in water.- Weak electrolyte

It is capable of acting as either an acid or a base depending upon the solute- Amphoteric solvent

The act of self-ionization of a solvent to produce both a conjugate acid and a conjugate base.- Auto-protolysis

A chemical species that bears both positive and negative charges.- Zwitterion

Explanation:

In the answer box we have various chemical terminologies and their definitions. In answering the question, you must carefully read through each definition, then check what option best matches that definition from the options provided.

Each definition applies only to one terminology as you can see in the answer above.

4 0

3 years ago

1. Which of the following nuclear equations is correctly balanced? (choices attached)

lawyer [7]

1. Balancing nuclear equations

Answer:

$_{18}^{37}\text{Ar} + _{-1}^{0}\text{e} \rightarrow _{17}^{37}\text{Cl}$

Explanation:

The main point to remember in balancing nuclear equations is that the sums of the superscripts (the mass numbers) and the subscripts (the nuclear charges) must balance.

Mass numbers: 37 + 0 = 37; balanced.

Charges: 18 + 1 = 17; balanced

B is wrong. Mass numbers not balanced. 6 +2(1) ≠ 4 + 3.

C is wrong. Mass numbers not balanced. 254 + 4 ≠ 258 + 2(1).

D is wrong. Mass numbers not balanced. 14 + 4 ≠ 17 + 2.

===============

2. Amount remaining

Answer:

D. 5.25 g

Explanation:

The half-life of Th-234 (24 da) is the time it takes for half the Th to decay.

After one half-life, half (50 %) of the original amount will remain.

After a second half-life, half of that amount (25 %) will remain, and so on.

We can construct a table as follows:

No. of Fraction Amount

half-lives t/(da) remaining remaining/g

1 24 ½ 21.0

2 48 ¼ 10.5

3 72 ⅛ 5.25

4 96 ¹/₁₆ 2.62

We see that 72 da is three half-lives, and the amount of Th-234 remaining is 5.25 g.

===============

3. Calculating the half-life

Answer:

a. 2.6 min

Explanation:

The fraction of the original mass remaining is 1.0 g/4.0 g ≈ ¼.

We saw from the previous table that it takes two half-lives to decay to ¼ of the original amount.

2 half-lives = 5.2 min Divide both sides by 2

1 half-life = 5.2 min/2 = 2.6 min

7 0

3 years ago