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3 years ago

Which of the following is a change of state

Chemistry

2 answers:

aalyn [17]3 years ago

7 0

Answer:

Please provide more info

Oksana_A [137]3 years ago

4 0

Answer:

A change of state would be like changing it into something different.

Explanation:

One example of changing state can be water changing into ice and then back into water because water is a state of matter.

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Refer to the illustration of the periodic table to determine which formula is correct.

Mekhanik [1.2K]

Answer:

D. MgO

Explanation:

We need to look at the charge of element. (Look at a periodic table for this)

Mg, which is Magnesium, has a charge of 2+ because it's in the second column, or group, from the left.

O, which is Oxygen, has a charge of 2- because it's in the second column, or group, from the right.

Since Mg is 2+, it's the cation and since O is 2-, it's the anion. We can put these two elements together into an ionic compound.

Mg^(2+) and O^(2-) becomes Mg2O2, where we can cancel the 2s: MgO.

Thus, the answer is D.

Hope this helps!

5 0

3 years ago

Explain your answer.

Lilit [14]

Answer:

14. (C) -3; 16. B. 0, 3

Explanation:

14. Ionic charge

X: ns²np³.

The element is three electrons short of having a complete octet.

It is likely to react chemically to add those three electrons and form an X³⁻ ion.

16. Orbitals in subshells

The n = 1 shell contains no p orbitals. All the other shells contain three p orbitals.

The n = 1 shell contains only one s orbital. Every higher shell contains a p subshell, and each p subshell contains three p orbitals.

3 0

3 years ago

An atom of helium has a radius of 31. pm and the average orbital speed of the electrons in it is about 4.4x 10 m/s Calculate the

otez555 [7]

The question is incomplete, here is the complete question:

An atom of helium has a radius of 31. pm and the average orbital speed of the electrons in it is about $4.4\times 10^6m/s$ . Calculate the least possible uncertainty in a measurement of the speed of an electron in an atom of helium. Write your answer as a percentage of the average speed, and round it to 2 significant digits

<u>Answer:</u> The percentage of average speed is 41 %

<u>Explanation:</u>

We are given:

Radius of helium atom = 31 pm = $31\times 10^{-12}m$ (Conversion factor: $1m=10^{12}pm$ )

So, diameter of helium atom = $(2\times r)=(2\times 31\times 10^{-12})=64\times 10^{-12}m$

The diameter of the atom will be equal to the uncertainty in position.

The equation representing Heisenberg's uncertainty principle follows:

$\Delta x.\Delta p=\frac{h}{2\pi}$

where,

$\Delta x$ = uncertainty in position = d = $64\times 10^{-12}m$

$\Delta p$ = uncertainty in momentum = $m\Delta v$

m = mass of electron = $9.1095\times 10^{-31}kg$

h = Planck's constant = $6.627\times 10^{-34}kgm^2/s^2$

Putting values in above equation, we get:

$64\times 10^{-12}m\times 9.1095\times 10^{-31}kg\times \Delta v=\frac{6.627\times 10^{-34}kgm^2/s}{2\times 3.14}\\\\\Delta v=\frac{6.627\times 10^{-34}kgm^2/s^2}{2\times 3.14\times 64\times 10^{-12}m\times 9.1095\times 10^{-31}kg}=1.81\times 10^6m/s$

To calculate the percentage of average speed, we use the equation:

$\text{Percentage of the average speed}=\frac{\text{Uncertainty in velocity}}{\text{Average orbital speed}}\times 100$

We are given:

Average orbital speed = $4.4\times 10^6m/s$

Putting values in above equation, we get:

$\text{Percentage of the average speed}=\frac{1.81\times 10^6m/s}{4.4\times 10^6m/s}\times 100\\\\\text{Percentage of the average speed}=41.\%$

Hence, the percentage of average speed is 41 %

3 0

4 years ago

What is an intermolecular force?

viva [34]

Answer: a force acting between two different molecules

Explanation:

APEX

4 0

4 years ago

The amount of protein in a sample was measured by the sample's absorbance of light at a given wavelength. Using standards, a bes

FinnZ [79.3K]

Answer:

Protein Concentration is 2.82mg/L

Explanation:

According to Beer-Lambert's Law, Absorbance is directly proportional to the concentration.

However, the concentration of a solution can be determined from a calibration curve, in which Absorbance is plotted on the y-axis and the Concentration on the x-axis.

Plotting the best line, the equation of line is used

y = mx + c

where y is absorbance = 0.150

m is slope = 0.0163

x is concentration

c is intercept = 0.104

inserting the values from the question

y = mx + c

0.150 = 0.0163x + 0.104

0.0163x = 0.150 - 0.104

0.0163x = 0.046

Divide both sides by 0.0163

0.0163x/0.0163 = 0.046/0.0163

x = 2.82

Concentration of protein = 2.82 mg/L

5 0

3 years ago