How many water molecules are need to break down an oligosaccharide that contains 10 glucose units?

A 25.00 mL sample containing an unknown amount of Al3+ and Pb2+ required 17.14 mL of 0.04907 M EDTA to reach the end point. A 50

dolphi86 [110]

Answer:

pAl³⁺ = 1,699

pPb²⁺ = 1,866

Explanation:

In this problem, the first titration with EDTA gives the moles of Al³⁺ and Pb²⁺, these moles are:

Al³⁺ + Pb²⁺ in 25,00mL = 0,04907M×0,01714L = 8,411x10⁻⁴ moles of EDTA≡ moles of Al³⁺ + Pb²⁺.

The molar concentration is 8,411x10⁻⁴ moles/0,02500L = 0,0336M Al³⁺+Pb²⁺.

In the second part each Al³⁺ reacts with F⁻ to form AlF₃. Thus, you will have in solution just Pb²⁺.

The moles added of EDTA are:

0,02500L×0,04907M = 1,227x10⁻³ moles of EDTA

The moles of EDTA in excess that react with Mn²⁺ are:

0,02064M × 0,0265L = 5,470x10⁻⁴ moles of Mn²⁺≡ moles of EDTA

That means that moles of EDTA that reacted with Pb²⁺ are:

1,227x10⁻³ moles - 5,470x10⁻⁴ moles = 6,800x10⁻⁴ moles of EDTA ≡ moles of Pb²⁺.

The molar concentration of Pb²⁺ is:

6,800x10⁻⁴mol/0,0500L = 0,0136 M Pb²⁺

Thus, molar concentration of Al³⁺ is:

0,0336M Al³⁺+Pb²⁺ - 0,0136 M Pb²⁺ = 0,0200M Al³⁺

pM is -log[M], thus pAl³⁺ and pPb²⁺ are:

pAl³⁺ = 1,699

pPb²⁺ = 1,866

I hope it helps!

3 0

3 years ago

What is the specific heat of a 123 g substance that requires 4.56 J of heat in

vladimir1956 [14]

Answer: A. $0.00301J/g^0C$

Explanation:

The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.

$Q=m\times c\times \Delta T$

Q = Heat absorbed = 4.56 J

m = mass of substance = 123 g

c = specific heat capacity = ?

Change in temperature , $\Delta T=T_f-T_i=12.32^0C$

Putting in the values, we get:

$4.56J=123g\times c\times 12.32^0C$

$c=0.00301J/g^0C$

The specific heat of a 123 g substance that requires 4.56 J of heat in order to increase its temperature by 12.32 °C is $0.00301J/g^0C$

8 0

3 years ago

The following chemical equation is unbalanced. When the equation is balanced, what is the coefficient for pure calcium (Ca)? A.

erik [133]

3Ca + 2AlPO4 -> 2Al + Ca3(PO4)2 . . .the coefficient for Ca is 3.

5 0

3 years ago

Read 2 more answers

What distinguishes a neutral atom from an ion

Aliun [14]

will they contain the same number of protons as electrons. By the meaning, an "ion" is an electrically charged particle produced by either removing electrons from the neutral atom to give a positive ion or adding electrons to a neutral atom to give a negative" ion".
hope i helped :)

6 0

3 years ago

How do you know sodium is highly reactive?

Stells [14]

Na (sodium) is highly electropositive. Its has 1 electron in its outermost orbit which is transferred to an electronegative atom to form an ionic bond.

It only needs to get rid of one valence electron to take part in a reaction. That's how it's highly reactive.

4 0

4 years ago