Why is the standard enthalpy formation of oxygen zero?

A solution of NaCl ( aq ) is added slowly to a solution of lead nitrate, Pb ( NO 3 ) 2 ( aq ) , until no further precipitation o

statuscvo [17]

Answer : The molarity of $Pb(NO_3)_2$ solution is, 0.352 M

Explanation :

First we have to calculate the moles of $PbCl_2$

$\text{Moles of }PbCl_2=\frac{\text{Given mass }PbCl_2}{\text{Molar mass }PbCl_2}$

Molar mass of $PbCl_2$ = 278.1 g/mol

$\text{Moles of }PbCl_2=\frac{19.58g}{278.1g/mol}=0.07041mol$

Now we have to calculate the moles of $CaCl_2$

The balanced chemical equation is:

$Pb(NO_3)_2(aq)+2NaCl(aq)\rightarrow PbCl_2(s)+2NaNO_3(aq)$

From the balanced reaction we conclude that

As, 1 mole of $PbCl_2$ produced from 1 mole of $Pb(NO_3)_2$

So, 0.07041 mole of $PbCl_2$ produced from 0.07041 mole of $Pb(NO_3)_2$

Now we have to calculate the molarity of $Pb(NO_3)_2$

$\text{Molarity of }Pb(NO_3)_2=\frac{\text{Moles of }Pb(NO_3)_2}{\text{Volume of solution in (L)}}$

$\text{Molarity of }Pb(NO_3)_2=\frac{0.07041mol}{0.200L}=0.352M$

Therefore, the molarity of $Pb(NO_3)_2$ solution is, 0.352 M

4 0

3 years ago

6.

RUDIKE [14]

Answer:

THE CURRENT REQUIRED TO PRODUCE 193000 C OF ELECTRICITY IS 35.74 A.

Explanation:

Equation:

Al3+ + 3e- -------> Al

3 F of electricity is required to produce 1 mole of Al

3 F of electricity = 27 g of Al

If 18 g of aluminium was used, the quantity of electricity to be used up will be:

27 g of AL = 3 * 96500 C

18 G of Al = x C

x C = ( 3 * 96500 * 18 / 27)

x C = 193 000 C

For 18 g of Al to be produced, 193000 C of electricity is required.

To calculate the current required to produce 193 000 C quantity of electricity, we use:

Q = I t

Quantity of electricity = Current * time

193 00 = I * 1.50 * 60 * 60 seconds

I = 193 000 / 1.50 * 60 *60

I = 193 000 / 5400

I = 35.74 A

The cuurent required to produce 193,000 C of electricity by 18 g of aluminium is 35.74 A

3 0

3 years ago

Compound a reacts with one equivalent of h2 in the presence of a catalyst to give methylcyclohexane. Compound a can be formed up

V125BC [204]

Answer:

The compound a is 1-methyl cyclohexene (see attachment for structure).

Explanation:

The reaction of 1-Bromo-1-methylcyclohexane with sodium methoxide is a second-order reaction since the methoxide ion is a strong base and also a strong nucleophile. This ion attacks the alkyl halide faster than the alkyl halide can ionize to produce a first-order reaction. However, we can not see the product of nucleophilic substitution. The SN₂ mechanism is blocked due to the impediment of the 1-Bromo-1-methylcyclohexane. The main product, according to the Zaitsev rule, is the 1-methyl cyclohexene, thus forming a double bond.

Then, this cyclohexene is hydrogenated to form the cyclohexane.

6 0

3 years ago

"A group of college students believes that herbal tea has remarkable restorative powers. To test their belief, they visit a loca

Georgia [21]

D) the college students

Explanation:

In the experiment conducted by staffs of the nursing home, the group of college students that came for the experiment are the subjects of the experiment. A subject is a person that participates in a research.

In this research, the college students are the human participants in the experiment.
There must be a mutual agreement between the researcher and the subject because the subject is one that is being tested to see an outcome.
A subject can quit a research if he/she deems it fit at any time.

Learn more:

Experiments brainly.com/question/5096428

#learnwithBrainly

7 0

2 years ago

If a substance is composed entirely of one type of atom, it is known as a(n) _______.

Firlakuza [10]

A substance is composed entirely of one type of atom, it is known as a Chemical element
because mixture contain more than one type of atom and it cannot be neutron or isotope
so correct option is B
hope it helps

8 0

3 years ago