Which of the following is a pure substance

The vapor pressure of water at 0c is 4.579 mmhg what is this pressure in pascals

Tom [10]

The conversion between mm mercury to pascals is (1 mmHg)/(133.32 pascals).
Therefore, we use the conversion:
4.579 mmHg * (133.32 pascals/1 mmHg) = 610.5 pascals

8 0

3 years ago

Determine the oxidation states of the elements in the compounds listed. None of the oxygen-containing compounds are peroxides or

Ahat [919]

Answer :

Oxidation number or oxidation state : It represent the number of electrons lost or gained by the atoms of an element in a compound.

Oxidation numbers are generally written with the sign (+) and (-) first and then the magnitude.

Rules for Oxidation Numbers are :

The oxidation number of a free element is always zero.
The oxidation number of a monatomic ion equals the charge of the ion.
The oxidation number of Hydrogen (H) is +1, but it is -1 in when combined with less electronegative elements.
The oxidation number of oxygen (O) in compounds is usually -2.
The oxidation number of a Group 17 element in a binary compound is -1.
The sum of the oxidation numbers of all of the atoms in a neutral compound is zero.
The sum of the oxidation numbers in a polyatomic ion is equal to the charge of the ion.

Now we have to determine the oxidation state of the elements in the compound.

(a) $H_2SO_4$

Let the oxidation state of 'S' be, 'x'

$2(+1)+x+4(-2)=0\\\\x=+6$

Hence, the oxidation state of 'S' is, (+6)

(b) $Ca(OH)_2$

Let the oxidation state of 'Ca' be, 'x'

$x+2(-2+1)=0\\\\x=+2$

Hence, the oxidation state of 'Ca' is, (+2)

(c) $BrOH$

Let the oxidation state of 'Br' be, 'x'

$x+(-2)+1=0\\\\x=+1$

Hence, the oxidation state of 'Br' is, (+1)

(d) $ClNO_2$

Let the oxidation state of 'N' be, 'x'

$-1+x+2(-2)=0\\\\x=+5$

Hence, the oxidation state of 'N' is, (+5)

(e) $TiCl_4$

Let the oxidation state of 'Ti' be, 'x'

$x+4(-1)=0\\\\x=+4$

Hence, the oxidation state of 'Ti' is, (+4)

(f) $NaH$

Let the oxidation state of 'Na' be, 'x'

$x+(-1)=0\\\\x=+1$

Hence, the oxidation state of 'Na' is, (+1)

4 0

3 years ago

Ozone is made of oxygen. What is the formula of ozone if 36g occupies 16.8L at STP?

Scilla [17]

The formula of ozone is O3.
Hope this helps~

6 0

4 years ago

A science student observes that a dissolvable antacid tablet acts faster in relieving stomach pain when taken with warm water th

LekaFEV [45]

Answer:the medication would not last as long

Explanation:

Because of the desolving of the tablet so quickly it would

4 0

4 years ago

Read 2 more answers

The neutralization of a 0.455 g sample of recrystallized aspirin required 38.6 mL of 0.100 M NaOH solution. An additional 25.0 m

Schach [20]

Answer:

E) Two of the above statements are true.

Explanation:

The options are:

A) Before the solution is titrated with HCl it is pink and when the color changes from pink to colorless, the moles of H*(aq) equals the moles of OH"(aq) used in the hydrolysis of the neutralized aspirin. TRUE. Before the solution is titrated, there is an excess of NaOH (Basic solution, phenolphtalein is pink). Then, at equivalence point, after the addition of HCl, the pH is acidic and phenolphtalein is colorless.

B) Before the solution is titrated with HCl it is colorless and when the color changes from colorless to pink, the moles of H*(aq) equals the excess moles of OH(aq) added. FALSE. As was explained, before the titration, the solution is pink.

C) 25.0 mL of 0.100 M NaOH was added to the sample to hydrolyze the neutralized aspirin in the solution. The titration with HCl allows us to determine the moles of excess OH(aq) added. Once we determine the moles of excess OH(aq), we can determine moles of OH"(aq) used in the hydrolysis of the neutralized aspirin, which is equal to the moles of aspirin in the recrystallized aspirin. TRUE. Aspirin requires an excess of base (NaOH) for a complete dissolution (Hydrolysis). Then, we add H+ as HCl to know the excess moles of OH-. As we know the added moles of OH-, we can find the moles of OH that reacted = Moles of aspirin.

D) We can determine the moles of aspirin in the recrystallized aspirin by titrating with the 0.100 M NaOH to the neutralization point. The purpose of the hydrolysis of the neutralized aspirin and the back-titration with the 0.100 M HCl is to confirm the moles of aspirin in the recrystallized aspirin. FALSE. NaOH can be added directly unyil neutralization point because, initially, aspirin can't be dissolved completely

E) Two of the above statements are true. TRUE

Right option is:

<h3>E) Two of the above statements are true.</h3>

3 0

3 years ago