Please help me!!!!!!

Answer:

4

Explanation:

Explanation:

As technology advances with time, it also enhances people's creativity. ... People are able to constantly search things and discover new information they didn't know before. It allows us to become educated and have an outlet to speak our mind

Answer:

B

Explanation:

Please give brainliest

The relative standard deviation for the set of data obtained by the student is 0.470%

The formula for calculating the relative standard deviation is given below as:

Relative standard deviation (RSD) = (S * 100)/x

where S stands for the standard deviation and x is the mean of the data set.

The following are the steps to calculate to determine the relative standard deviation using the given formula:

Step 1: Calculate the mean of the numbers in the data set.

mean, x = sum of numbers / number of numbers

(40.220 + 40.654 + 40.314 + 40.165 + 40.554)/5

mean = 40.381 g/mol

Step 2: Subtract the mean from each number in the data to determine the deviation for each number and then square the deviations.

(40.220 - 40.381)² = 0.0259

(40.654 - 40.381)² = 0.0745

(40.314 - 40.381)² = 0.00449

(40.165 - 40.381)² = 0.0466

(40.554 -40.381)² = 0.0299

Step 3: Sum the squared deviations.

0.0259 + 0.0745 + 0.00449 + 0.0466 + 0.0299 = 0.181

Step 4: Determine the variance by dividing the sum of the squared deviations by the total number of values.

Variance = 0.181/5 = 0.0362

Step 6: Determine the standard deviation of the data by taking square root of the variance.

Standard deviation, S = √0.0362 = 0.190

Step 7: Determine the relative standard deviation by inserting the values in the formula, (RSD) = (S * 100)/x

RSD = (0.190 * 100)/40.381

RSD = 0.470%

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Answer:

B. Light waves or energy

Explanation:

Einstein argued that gravity isn't a force at all. He described it as a curvature of time and space caused by mass and energy.

Explanation:

One mole of NaOH weighs 40gm.

Now 2M solution of NaOH indicates 2 moles of NaOH in 1 litre of water.

So the above question can now be simplified as …if one litre of water contains 80gm(2 moles) of NaOH, then how many grams of NaOH would 250ml solution of the same contain?

Using unitary method,

1000ml corresponds to 80gm NaOH…

1000/4 ml(250ml) corresponds to 80/4 gm NaOH…

Therefore, for 250ml of 2M NaOH, 20 gm of NaOH needs to be added to water.

It's in the last paragraph of this website.

https://community.ptc.com/t5/PTC-Mathcad/AP-Chemistry-Problem-Help/td-p/64410

The bubbling that occurs when the methanol is added to the dry sand indicate that there is no chemical reaction between  sand and methanol rather it is just methanol displacing air between sand .

Chemical reactions are defined as reactions which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical reaction.

There are several characteristics of chemical reactions like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.

There are three types of chemical reactions:

1) inorganic reactions

2)organic reactions

3) biochemical reactions

During chemical reactions atoms are rearranged and changes are accompanied by an energy change as new substances are formed.

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Answer:

the given equation is

Fe2o3+co-- Fe+co2

Balanced chemical equation is

Fe2o3 + 3co-- 2Fe+3co2

Explanation:

First write down the basic chemical equation with the reactants and products,

[tex]\text{P}_4+\text{ Cl}_2\to\text{ PCl}_3[/tex]

Balancing the chemical equation*,

[tex]\text{P}_4 (s) + 6 \text{Cl}_2 (g) \to 4 \text{PCl}_3 (l)[/tex]

[tex]\color{blue}\text{Note: To balance any chemical equations, we should ensure the number of atoms of each elements are the same on both the product and reactant side.}[/tex]

[tex]\color{blue}\text{The phosphorous molecule has 4 P, but the }\text{PCl}_3\text{ molecule on the product side only has one P atom. Therefore, we need 4 }\text{PCl}_3\text{ molecules to balance.}[/tex]

[tex]\color{blue}\text{But that will mean we have }4\cdot 3=12\text{Cl atoms on the product side. So we need 6 }\text{Cl}_2 \text{ molecules on the reactant side.} [/tex]

Answer:

The correct choice is option b. ethanol < Mg(NO3)2 < NaCl

Explanation:

Ethanol = 0.100 m

Mg(NO3)2 = 0.15 m

NaCl = 0.18 m

The molar concentration of NaCl is the highest, which is why its boiling point will be the highest, too.

Answer:

To determine how many total electrons there are, add the amount of charge to the atomic number

Explanation:

For example, N3- has a -3 charge which means it has 3 more electrons than a neutral nitrogen atom. Nitrogen's atomic number is 7, therefore this ion has 10 electrons.

Answer:

A) 14,500 kPa

B)  6 atm

C)  23.443 atm

D)  898.6  mmHg

Explanation:

Answer:

(from largest to smallest), macroscopic, microscopic, submicroscopic.

Explanation:

Explanation:

The correct order of these from largest to smallest is macroscopic, microscopic, and submicroscopic.

Macroscopic is a term used for things that can be easily seen by the eyes. They are of large size. Macroscopic are those items like rubber, mountains, a bottle, etc.

Microscopic items are those items that are minimum in size and can not be seen by eyes. They are seen by using microscopes. They are microorganisms, cells, cell organelle, etc.

Submicroscopic matters are those objects or substances that made up matter. They are present but can not be seen by eyes. They are electrons, protons, etc. so the correct order of them according to largest to smallest is macroscopic, microscopic, and submicroscopic.

Thus, the correct order is macroscopic, microscopic, and submicroscopic.

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Answer:

When an element is oxidized, it loses electrons

Answer:

The last option is the correct answer.

Explanation:

When an element is oxidized, it loses electrons. But when an element is reduced, it gains electrons. This is the basis of redox reactions.

However, an oxidizing agent oxidizes something else, and gets reduced, therefore gaining electrons. Meanwhile, a reducing agent reduces something else, and gets oxidized in the process, losing its own electrons.

The first quarter moon occurs halfway between new moon and full moon.

From our perspective, the moon is partially lighted and is 90 degrees away from the sun in the sky.

We refer to it as the "first quarter" since the moon has only circled the Earth once since the new moon.

From Earth, you can view one-quarter of the moon, or half of the moon's illuminated side, which seems to be one-half of a pie.

Therefore, The first quarter moon occurs halfway between new moon and full moon.

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Answer:

2.2309

Explanation:

Density=Mass÷Volume

Volume=mass÷Volume

             =23.210÷11.3

             =2.2309

Answer:

3.50 mol x 6.022 x 10^23

= 2.11 x 10^24 carbon atoms

Explanation:

1. moles = grams/molar mass

2. (mass nitrogen/mass amm sulfide)*100 = ??

3. mass Hg = volume x density

Then convert to moles.

Then remember there are 6.022E23 atoms for every mole.

Answer:

Jowhwbeejwieiebbej sssie ksihejwiiwb isjbeiis

Density is simply defined as the mass per unit volume of a substance. Mathematically, it is expressed as:

[tex]Density = \frac{mass}{volume }[/tex]

To solve the question given above, we'll begin by calculating the volume of the metal. This can be obtained as follow:

Volume of water = 25 mL

Volume of water + metal = 46.5 mL

Volume of metal = (Volume of water + metal) – (Volume of water)

Volume of metal = 46.6 – 25

Finally, we shall determine the density of the metal. This can be obtained as follow:

Mass of metal = 254 g

Volume of metal = 21.5 mL

[tex]Density = \frac{mass}{volume }\\\\Density = \frac{254}{21.5} \\[/tex]

Therefore, the density of the metal is 11.81 g/mL

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Answer:

A mixture can be separated by looking at the physical properties of the components of the mixture.

Since salt is soluble in water, water can be added to the mixture to dissolve the salt.

The bar magnet is now introduced in order to remove the iron filings since they are attracted by a magnet.

The solution is filtered to separate the sand from the salt solution.

Lastly, the salt solution is heated to dryness to drive away the water and obtain the solid salt.

Hence the mixture has been separated into its components using their individual physical properties. Option A is the correct answer.

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Answer:

is it a b c or d

Explanation:

Answer:  60 g/mban

Explanation:  I don't know what an "mban" is, but the density of this alien rock would be 60 grams/mban.  Density = Mass/Volume

Answer:

Chelate, any of a class of coordination or complex compounds consisting of a central metal atom attached to a large molecule, called a ligand, in a cyclic or ring structure. An example of a chelate ring occurs in the ethylenediamine-cadmium complex:

The ethylenediamine ligand has two points of attachment to the cadmium ion, thus forming a ring; it is known as a didentate ligand. (Three ethylenediamine ligands can attach to the Cd2+ ion, each one forming a ring as depicted above.) Ligands that can attach to the same metal ion at two or more points are known as polydentate ligands. All polydentate ligands are chelating agents.

Chelates are more stable than nonchelated compounds of comparable composition, and the more extensive the chelation—that is, the larger the number of ring closures to a metal atom—the more stable the compound. This phenomenon is called the chelate effect; it is generally attributed to an increase in the thermodynamic quantity called entropy that accompanies chelation. The stability of a chelate is also related to the number of atoms in the chelate ring. In general, chelates containing five- or six-membered rings are more stable than chelates with four-, seven-, or eight-membered rings.

Explanation:

Mass is a measure of inertia

The variable that affect mass of a body is the amount of matter present in the body

The reason for arriving at the above statement is as follows:

Mass is the property of a body that indicates the quantity of matter contained in the body and also a measure of the body's resistance to acceleration

In an experiment to determine the variables that affect mass, using a weight balance and paper clips, the observation is that as the quantity of the paper clips are increases on one side of the balance, the balance tilts lower on the side bearing the larger number of paper clips indicating a larger mass

Therefore, the variable that affect mass is the quantity of matter (material) present

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Answer:

b

Explanation:

well I really don't remember but I think it's b

The mass of 125 mL of bromine and the volume occupied by 85 g of bromine are:  

Density is simply defined as the mass of an object per unit volume of the object. It can be expressed mathematically as

[tex]Density = \frac{mass}{volume }[/tex]

Density = 3.12 g/mL

Volume = 125 mL

[tex]Density = \frac{mass}{volume} \\\\3.12 = \frac{mass}{125}[/tex]

Cross multiply

Mass = 3.12 × 125

Therefore, the mass of bromine is 390 g

Density = 3.12 g/mL

Mass = 85 g

[tex]Density = \frac{mass}{volume } \\\\3.12 = \frac{85}{volume }[/tex]

Cross multiply

3.12 × Volume = 85

Divide both side by 3.12

[tex]Volume = \frac{85}{3.12}\\\\[/tex]

Therefore, the Volume of bromine is 27.24 mL

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