All categories

4 years ago

7.26 of a hydrate, Cu(NO3)2.xH2O, formed 2.4 g copper(II) oxide.

Chemistry

1 answer:

goldfiish [28.3K]4 years ago

6 0

Number of moles= mass/ molar mass

Or n=m/MM

n = number of moles

m = mass

MM = molar mass

1) n CuO = 2.4g / 79.54g/mol = 0.03 mol CuO

2) n Cu(NO3)2.xH2O = 7.26 g / 205.6 = 0.035 moles of Cu(NO3)2.xH2O

3) 205.6 g

Cu = 63.5 g

N = 14g

O =16g

H= 1 g

63.5+ (14+(16*3))*2+1*2+16 =205.6 g

4) yes is 188g

5) I don’t know, I assume was 1

You might be interested in

For the following reaction, Kc = 15 at 700 K. 2 NO(g) + Cl2(g) ⇄ 2 NOCl(g) If we have [NO] = 0.15 M, [Cl2] = 0.15 M, [NOCl] = 0.

vovangra [49]

Answer : The correct option is, The equilibrium will shift to the left until all the NOCl is used up.

Explanation :

Reaction quotient (Q) : It is defined as the measurement of the relative amounts of products and reactants present during a reaction at a particular time.

The given balanced chemical reaction is,

$2NO(g)+Cl_2(g)\rightarrow 2NOCl(g)$

The expression for reaction quotient will be :

$Q=\frac{[NOCl]^2}{[NO]^2[Cl_2]}$

In this expression, only gaseous or aqueous states are includes and pure liquid or solid states are omitted.

Now put all the given values in this expression, we get

$Q=\frac{(0.40)^2}{(0.15)^2(0.15)}=47.4$

The given equilibrium constant value is, $K=15$

Equilibrium constant : It is defined as the equilibrium constant. It is defined as the ratio of concentration of products to the concentration of reactants.

There are 3 conditions:

When $Q>K$ that means product > reactant. So, the reaction is reactant favored.

When $Q$ that means reactant > product. So, the reaction is product favored.

When $Q=K$ that means product = reactant. So, the reaction is in equilibrium.

From the above we conclude that, the $Q>K$ that means product > reactant. So, the reaction is reactant favored that means reaction must shift to the reactants to be in equilibrium or shift to the left side.

Hence, the correct option is, The equilibrium will shift to the left until all the NOCl is used up.

6 0

3 years ago

Calculate the amount of heat released in the combustion of 10.5 grams of Al with 3 grams of O2 to form Al2O3(s) at 25°C and 1 at

ElenaW [278]

Answer : The amount of heat released in the combustion is, 209.5 kJ

Explanation :

First we have to calculate the moles of Al and $O_2$ .

$\text{ Moles of }Al=\frac{\text{ Mass of }Al}{\text{ Molar mass of }Al}=\frac{10.5g}{27g/mole}=0.389moles$

$\text{ Moles of }O_2=\frac{\text{ Mass of }O_2}{\text{ Molar mass of }O_2}=\frac{3g}{32g/mole}=0.188moles$

Now we have to calculate the limiting and excess reagent.

The balanced chemical reaction will be:

$4Al+3O_2\rightarrow 2Al_2O_3$

From the balanced reaction we conclude that

As, 3 mole of $O_2$ react with 4 mole of $Al$

So, 0.188 moles of $O_2$ react with $\frac{4}{3}\times 0.188=0.251$ moles of $Al$

From this we conclude that, $Al$ is an excess reagent because the given moles are greater than the required moles and $O_2$ is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of $Al_2O_3$

From the reaction, we conclude that

As, 3 mole of $O_2$ react to give 2 mole of $Al_2O_3$

So, 0.188 moles of $O_2$ react to give $\frac{2}{3}\times 0.188=0.125$ moles of $Al_2O_3$

Now we have to calculate the amount of heat released in the combustion.

As, 1 mole of $Al_2O_3$ releases amount of heat = 1676 kJ

So, 0.125 mole of $Al_2O_3$ releases amount of heat = $0.125\times 1676kJ=209.5kJ$

Thus, the amount of heat released in the combustion is, 209.5 kJ

4 0

3 years ago

An object measures 6.2cm x 13.7cm x 26.9cm. Which value is the length of the object?

kotykmax [81]

Answer:

Explanation:

The length is usually the longest side.

That would mean that 26.9 is the length.

6 0

3 years ago

Using Newton’s laws of motion, describe the motion of a roller coaster and analyze the forces acting on the roller coaster at di

Illusion [34]

We can apply Newton's third law of motion in roller coaster.

Explanation:

If we are planning to make a roller coaster with elevations and turn then we need to apply newton’s law of motions, kinetic energy and potential energy.

Newton’s third law of motion says that “ for every action, there is an equal and opposite reaction”. Newton’s third law of motion applies between the tract and ride vehicles.

If we neglect the air resistance and friction, Roller coaster car will always experience two types of forces which are gravitational force and normal force. The normal force is acting perpendicular to the track and gravitational for is also acting downwards.

Whenever the tracts get moving the gravitational force is attracting roller coaster to downward. So this will get accelerates. In the majority of the roller coasters, the hill will decrease with height as the train moves along the tract.

3 0

3 years ago

Lithium has 2 stable isotopes Li-6 and Li-7. One of them has an abundance of 92.5% and the other has an abundance of 7.5%. Knowi

nordsb [41]

Answer : The more abundant isotope is, Li isotope-7

Explanation :

Average atomic mass of an element is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.

For Li isotope-7 :

Mass of Li isotope-7 = 7 amu

Fractional abundance of Li isotope-7 = 92.5 %

For Li isotope-6 :

Mass of Li isotope-6 = 6 amu

Fractional abundance of Li isotope-6 = 7.5 %

Average atomic mass of Li = 6.941 amu

As we know that the more abundant isotope is that whose percentage abundant will be more and atomic mass of isotope will be near to average atomic mass of isotope.

From this we conclude that, the percentage abundant of Li isotope-7 is more and their atomic mass is near to average atomic mass.

Hence, the more abundant isotope is, Li isotope-7

7 0

4 years ago