How many moles are equal to 89.23 g of calcium nitrate?

Please help I need a answer to both

irga5000 [103]

Hi , I’m really sorry because I just have the first question... so here it is :

So it is 0.52 mol .

Have a nice day .

3 0

2 years ago

Calculate the wavelength, in nanometers, of the light emitted by a hydrogen atom when its electron fallsfrom the n = 7 to the n

Helga [31]

Answer:

λ=2167.6 nm

The wavelength of light emitted is 2167.6 nm.

Explanation:

We recall that Eₙ= $\frac{-2.18*10^{-18} J}{n^{2} }$

since there was transition from n7 to n=4 we will first calculate the change in the energy i.e ΔE

ΔE=E₄-E₇

ΔE= $-2.18*10^{-18} J(\frac{1}{4^{2} } -\frac{1}{7^{2} } )$

ΔE=-9.1760*10^-20 J

Now:

|ΔE|=Energy of photon=h*v=h*c/λ

λ=h*c/|ΔE|

λ= $\frac{6.63*10^{-34}J.s*3.00*10^{8}m/s }{9.1760*10^{-20} J }$

λ=2.1676*10^-6 m

λ=2167.6*10^-9 m

λ=2167.6 nm

The wavelength of light emitted is 2167.6 nm.

5 0

3 years ago

A student wants to measure the entropy of ice. What should the student do?

Helen [10]

Answer: Option (c) is the correct answer.

Explanation:

Entropy is defined as the degree of randomness. This means that more is the number of collisions taking place between atoms of a substance more will be the randomness.

Therefore, more will be the entropy of substance. We cannot measure the entropy but we can measure the change in entropy of a substance.

A thermometer is a glass tube that contains a liquid column generally mercury, and it is usually used to measure the temperature of human body.

A calorimeter is a device or apparatus that is used in a chemical reaction to measure the amount of heat involved.

Therefore, we can conclude that the student can't measure entropy directly, only an entropy change.

6 0

2 years ago

Hello, I study Home MS Physical Science B-IC. Are there quizlets I can look up for the cumulative exam I have to take today?

Ludmilka [50]

Yes if you search up your subject or topic then put quizlet you’ll find your answer but you may need to login in to get the best experience of studying that you want

8 0

2 years ago

You must answer all questions to get credit for this assignment. Use the notes above and/or the textbook to help you find the an

Allisa [31]

Explanation:

(1). It is known that in a reaction equation, reactants are placed or written on left hand side and products are written on the right hand side.

For example, $N_{2} + 3H_{2} \rightarrow 2NH_{3}$

Hence, in a reaction equation you start with the reactants and end up with the products.

(2). The number of atoms in a reaction will remain the same because according to the law of conservation of mass, mass of reactants will be equal to the mass of products.

Therefore, number of atoms on the reactant side will be equal to the number of atoms on product side.

7 0

2 years ago