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2 years ago

Does matter have weight and take up space?

Chemistry

1 answer:

miss Akunina [59]2 years ago

3 0

Explanation:

All matter has mass and occupies space. Volume is a measure of how much space an object occupies. ... "Mass" only depends on how much matter is in an object. "Weight", on the other hand, depends on how strongly gravity pulls on an object.

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calculate the frequency of the light emitted by a hydrogen atom during a transition of its electron from the n = 3 to n = 1 ener

MissTica

Answer:

$\nu=2.92\times 10^{15}\ Hz$

Explanation:

The expression for the energy of an electron in the nth orbit is:-

$E_n=-2.18\times 10^{-18}\times \frac{1}{n^2}\ Joules$

For transitions:

$Energy\ Difference,\ \Delta E= E_f-E_i =-2.18\times 10^{-18}(\frac{1}{n_f^2}-\frac{1}{n_i^2})\ J=2.18\times 10^{-18}(\frac{1}{n_i^2} - \dfrac{1}{n_f^2})\ J$

$\Delta E=2.18\times 10^{-18}(\frac{1}{n_i^2} - \dfrac{1}{n_f^2})\ J$

Given, $n_i=3\ and\ n_f=1$

$\Delta E=2.18\times 10^{-18}(\frac{1}{3^2} - \dfrac{1}{1^2})\ J$

$\Delta E=-1.94\times 10^{-18}\ J$ (negative sign indicates energy release)

Also, $E=h\times \nu$

Where,

h is Plank's constant having value $6.626\times 10^{-34}\ Js$

$1.94\times 10^{-18}=6.626\times 10^{-34}\times \nu$

$\nu=2.92\times 10^{15}\ Hz$

3 0

2 years ago

Chemistry help! Zoom in to see better!!

Julli [10]

Answer:

2.5 moles of Al

Explanation:

We'll begin by calculating the number of mole in 127 g of Al₂O₃. This can be obtained as follow:

Mass of Al₂O₃ = 127 g

Molar mass of Al₂O₃ = 101.961 g/mol

Mole of Al₂O₃ =?

Mole = mass / molar mass

Mole of Al₂O₃ = 127 / 101.961

Mole of Al₂O₃ = 1.25 mole

Finally, we shall determine the number of mole of Al that reacted. This can be obtained as follow:

4Al + 3O₂ —> 2Al₂O₃

From the balanced equation above,

4 moles of Al reacted to produce 2 moles of Al₂O₃.

Therefore, Xmol of Al will react to produce 1.25 moles of Al₂O₃ i.e

Xmol of Al = (1.25 × 4)/2

Xmol of Al = 2.5 moles.

Thus, 2.5 moles of Al is needed for the reaction.

4 0

2 years ago

What is the pH of a solution of H2SO that has (H3O+) = 5.45 x 10^-5 M?

Serggg [28]

B fncndhjrgzhzbbzhdhhd

6 0

2 years ago

Read 2 more answers

How manymoles of each ion are present in 175 mL of 0.147 M Fe2(SO4)3?

lilavasa [31]

Answer: 0.0257 moles of $Fe^{3+}$ and 0.0257 moles of $SO_4^{2-}$

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

$Molarity=\frac{moles}{\text {Volume in L}}$

moles of $Fe_2(SO_4)_3=Molarity\times {\text {Volume in L}}=0.147\times 0.175L=0.0257moles$

The balanced reaction for dissociation will be:

$Fe_2(SO_4)_3\rightarrow Fe^{3+}+SO_4^{2-}$

According to stoichiometry:

1 mole of $Fe_2(SO_4)_3$ gives 1 mole of $Fe^{3+}$ and 1 mole of $SO_4^{2-}$

Thus there will be 0.0257 moles of $Fe^{3+}$ and 0.0257 moles of $SO_4^{2-}$

8 0

3 years ago

A gas occupies the volume of 215ml at 15C and 86.4kPa?

kherson [118]

Answer:

About 0.1738 liters

Explanation:

Using the formula PV=nRT, where p represents pressure in atmospheres, v represents volume in liters, n represents the number of moles of ideal gas, R represents the ideal gas constant, and T represents the temperature in kelvin, you can solve this problem. But first, you need to convert to the proper units. 215ml=0.215L, 86.4kPa is about 0.8527 atmospheres, and 15C is 288K. Plugging this into the equation, you get:

$0.8527\cdot 0.215=n \cdot 0.0821 \cdot 288\\n\approx 7.754 \cdot 10^{-3}$

Now that you know the number of moles of gas, you can plug back into the equation with STP conditions:

$1V=7.754 \cdot 10^{-3} \cdot 0.0821 \cdot 273\\V\approx 0.1738L$

Hope this helps!

3 0

3 years ago