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stich3 [128]
3 years ago
14

Which substance can not be decomposed by a chemical change?

Chemistry
2 answers:
Dvinal [7]3 years ago
7 0
Copper. It's copper because it is an element, not a compound substance, so its already in its basic chemical form ^u^
max2010maxim [7]3 years ago
5 0
B. Copper since the rest of the choices are compounds. Copper is an element.
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You wish to prepare a buffer consisting of acetic acid and sodium acetate with a total acetic acetate plus acetate concentration
vovangra [49]

<u>Ans: Acetic acid = 90.3 mM and Sodium acetate = 160 mM</u>

Given:

Acetic Acid/Sodium Acetate buffer of pH = 5.0

Let HA = acetic acid

A- = sodium acetate

Total concentration [HA] + [A-] = 250 mM ------(1)

pKa(acetic acid) = 4.75

Based on Henderson-Hasselbalch equation

pH = pKa + log[A-]/[HA]

[A-]/[HA] = 10^(pH-pKa) = 10^(5-4.75) = 10^0.25 = 1.77

[A-] = 1.77[HA] -----(2)

From (1) and (2)

[HA] + 1.77[HA] = 250 mM

[HA] = 250/2.77 = 90.25 mM

[A-] = 1.77(90.25) = 159.74 mM



7 0
3 years ago
A balloon occupies 1.50 L with 0.205 mol of carbon dioxide. How many moles would be required to increase the size of the balloon
Gekata [30.6K]

Answer:

0.683 moles of the gas are required

Explanation:

Avogadro's law relates the moles of a gas with its volume. The volume of a gas is directely proportional to its moles when temperature and pressure of the gas remains constant. The law is:

V₁n₂ = V₂n₁

<em>Where V is volume and n are moles of 1, initial state and 2, final state of the gas.</em>

<em />

Computing the values of the problem:

1.50Ln₂ = 5L*0.205mol

n₂ = 0.683 moles of the gas are required

<em />

8 0
3 years ago
How many moles are there in 5.699 liters of neon gas at STP? Express your answer with the appropriate significant figures and un
Svetradugi [14.3K]

Answer:

The number of moles: 0.25442 moles

Explanation:

One mole of Neon gas will occupy 22.4 at STP.

5.699L consists of \frac{5.699}{22.4} = 0.25442 moles.

4 0
3 years ago
PLEASE HELP! DUE IN 5 MINUTES! ( 10 points )
max2010maxim [7]

Answer:

C

Explanation:

3 0
3 years ago
Read 2 more answers
An aqueous solution of a soluble compound (a nonelectrolyte) is prepared by dissolving 33.2 g of the compound in sufficient wate
Alecsey [184]
M=n(pie)/RT
n=osmotic pressure(1.2 atm)
M=molar  of the  solution
R=gas  constant(0.0821)
T=  temperature  in  kelvin 25+273
M=[1.2atm /(0.0821L atm/k mol x  298k)]=0.049mol L
M= moles  of  the  solute/ litres  of solution(250/1000)
0.049=  y/0.25
moles  of  solute is therefore =0.01225mol
molar  mass=33.29 g/0.01225mol=2.7 x10^3g/mol


6 0
3 years ago
Read 2 more answers
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