I need help with this quickly! thank you ;-;

Answer:

4.06×10^23

Explanation:

1 mole has 6.023×10^23 molecules

0.675 moles have (6.023×10^23×0.675) molecules

Answer:

I think 20

Explanation:

Becu of science

Answer:

hope it helps...

Explanation:

Atomic Number as the Basis for the Periodic Law

Assuming there were errors in atomic masses, Mendeleev placed certain elements not in order of increasing atomic mass so that they could fit into the proper groups (similar elements have similar properties) of his periodic table.

Answer:

Mass = 331.17 g

Explanation:

Given data:

Mass in gram = ?

Number of atoms of K₂SO₄ = 1.18 × 10²⁴ atoms

Solution:

Avogadro number:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.  The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ atoms

1.18 × 10²⁴ atoms × 1 mol / 6.022 × 10²³ atoms

0.19× 10¹ mol

1.9 mol

Mass of K₂SO₄:

Mass = number of moles × molar mass

Mass = 1.9 mol × 174.3 g/mol

Mass = 331.17 g

Answer:

B-After the 3s sublevel is filled with two electrons, each additional electron goes into the 3p sublevel.

Explanation:

Edmentum

Answer:

Does a magnet attract the element?

Explanation:

This is because, the attraction of an element by a magnet is a purely physical property. It has to do with the orientation of the electrons in the element. It does not tell us of the composition of the element or how it reacts with other elements. Whereas, the other questions deal with the chemical properties of the element. That is, how it reacts with other elements or substances.

Answer:

375 grams

Explanation:

The percent yield if 155 grams of calcium carbonate is treated with 250 grams of hydrochloric acid and 142 grams of calcium chloride is obtained is 82.55%

Percent yield is defined as the amount of product actually made compared with the maximum calculated yield. It is the ratio of actual yield to the theoretical yield.

Mass of calcium carbonate = 155 g

Mass of HCl = 250g

Mass of calcium chloride product = 142 g

Moles of calcium carbonate = 155 / 100 = 1.55 moles

Moles of HCl = 250 / 36.5 = 6.85 moles

Mass of calcium chloride = Moles x Molar mass

                                          = 1.55 mole x 111 g/ mole

                                          = 172 g /mole

Theoretical yield = 172 g

Actual yield = 142 g

Percent yield = Actual yield / Theoretical yield x 100
                      = 142 / 172 x 100

                      = 82.55 %

Thus, the percent yield if 155 grams of calcium carbonate is treated with 250 grams of hydrochloric acid and 142 grams of calcium chloride is obtained is 82.55%

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Mercury is in a liquid state

Mercury's melting point is somewhere around -34 Degrees Celcius. Thus it should be assumed it will be a liquid at this temperature. Not a gas however as mercury's boiling point is somewhere in the 600 Degree range

Answer:

its cold

Explanation:

Answer:

Did you put that in right because i've never heard of a compound called that nor is there a compound called that on the internet

Explanation:

You must of put that in wrong

Answer:

unbalanced I know you should know to

false

Explanation:photosynthesis takes place inside an organelle called a chloroplast. For plants, chloroplast-containing cells exist in the mesophyll.

Answer:

5 hours is 300 minutes so it goes 1 mile per minute. So 82 minutes = 1 hour and 22 minutes.

Explanation:

So if the car goes 1 mile every minute to reach 82 miles you have to

1 x 82 = 82 minutes converted into hourse = 1 hour and 22 minutes :)

Answer:

I believe it's an example of velocity

Explanation:

This is because 85miles/hour south is giving both magnitude (85miles/hour) and direction (south)

Answer:

Yeast is used for the leavening of bread. Yeast uses the sugars and oxygen in dough to produce more yeast cells and carbon dioxide gas. The carbon dioxide makes the dough rise which gives the bread a light and spongy texture. Yeast also works on the gluten network.

Explanation:

Answer:

does friction talks ? friction is a oppossing force tho

Answer:

3.67 L

Explanation:

From the question given above, the following data were obtained:

Initial temperature (T1) = 300 K

Initial volume (V1) = 4 L

Final temperature (T2) = 275 K

Final volume (V2) =?

Thus, we can obtain the final volume (i.e the new volume) of the balloon by using the Charles law equation as shown below:

V1 /T1 = V2 /T2

4/300 = V2/275

Cross multiply

300 × V2 = 4 × 275

300 × V2 = 1100

Divide both side by 300

V2 = 1100 / 300

V2 = 3.67 L

Therefore, the new volume of the balloon is 3.67 L

Answer:

Explanation:

The chemical elements are arranged in order of increasing atomic number. The horizontal rows are called periods and the vertical columns are called groups. Elements in the same group have similar chemical properties. This is because they have the same number of outer electrons and the same valency.

Answer:

B. Which type of teeth are most important in crushing food?

Explanation:

According to the question physical changes ought to be entered into column A while chemical changes ought to be entered into column B.

The crushing of food is a physical change. It does not involve any chemical transformation of the food material.The other options involve some sort of chemical transformation taking place on the food material being digested.

C

Pure water is at 7, and the bases are above 7 and the acids are below 7.

The pH of the solution that is classified as a weak base is 10. Details about weak bases can be found below.

pH of a solution refers to the degree of acidity or alkalinity of that solution.

The pH scale reads from 1 - 14 where the following applies:

A weak base will have a pH close to neutral, therefore, the pH of the solution that is classified as a weak base is 10.

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Answer:

Noble games are the least reactive because their outer shells are already full with 8 electrons.

Answer:

B: Mercury

Explanation:

Yuh

Answer:

Catalyse

Note that I'M NOT A SCIENCE TEACHER! I MIGHT BE INCORRECT, DOUBLE CHECK YOUR ANSWER!

Stay safe and Merry Christmas! :)

Answer:

Catalyse

Explanation:

Catalysis is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst.

Top answer is most likely true

Answer:

It is newtons First Law:)

Explanation: