Can someone help with 1 2 3 please I give you brainlest

Answer:

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\[/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

[tex]n = \frac{8.72 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 14.48504...[/tex]

We have the final answer as

Hope this helps you

Using magnesium ribbon instead of powdered magnesium decrease the rate of reaction between magnesium and air.

Rate of reaction tells about the duration of the completion of the reaction.

Rate of any reaction is directly proportional to the concentration and surface area of the reactant, temperature, catalyst, no. of collision, activation energy, etc.

So, if we magnesium in the ribbon instead of powdered magnesium the surface area of the reactant side decreases which results in the decrease of the rate of reaction.

Hence, option (D) is correct i.e. rate of reaction decreases on using magnesium ribbon instead of powdered magnesium.

To know more about rate of reaction, visit the below link:

https://brainly.com/question/1898560

Answer:

4.04433566 L (433566 repeating)

Explanation:

2.52 is divided by 28.6 is 0.0881118 (881118 repeating). multiply 0.0881118 (881118 repeating) by 45.9 to get 4.04433566 L (433566 repeating).

Answer:

c

Explanation:

metamorphic rocks

Answer:

C. Metamorphic

Explanation:

Answer: c (the amount of empty space between the water particles will decrease)

Explanation: i got it right:)

Answer: A monopoly is the absence of competition in the market.

Explanation:

In such circumstances, the market creates a monopoly of one producer who takes huge capital and dictates prices. An example of a monopoly on the market is the existence of only one company that makes up the entire economic branch. In such circumstances, the monopolist can increase the product's price without losing the entire sale, i.e., operating successfully. In that situation, the monopolist remains the only one on the market, and the competition has no access to the market.

Answer:

One mole of sugar is a considered as atomic mass. The atomic mass of sugar is 342 g. Rate of 1 kg of sugar is 40 Rs. Thus, the rate of 342 gram of sugar= 40x342/1000 = 13.68 Rupees

Explanation:

Answer:

Percent yield = 94.62%

Explanation:

Given data:

Actual yield of BeBr₂ = 1.23 mol

Theoretical yield of BeBr₂ = 220 g

Percent yield = ?

Solution:

Theoretical yield in moles:

Number of moles = mass/molar mass

Number of moles = 220 g/168.82 g/mol

Number of moles = 1.30 mol

Percent yield:

Percent tiled = actual yield / theoretical yield × 100

by putting values,

Percent yield = 1.23 mol / 1.30 mol × 100

Percent yield = 0.9462 × 100

Percent yield = 94.62%

Answer:

w = -531 kJ

1. Work was done by the system.

Explanation:

Step 1: Given data

Step 2: Calculate the work done (w)

We will use the following expression.

ΔU° = q + w

w = ΔU° - q

w = 156 kJ - 687 kJ

w = -531 kJ

By convention, when w < 0, work is done by the system on the surroundings.

Answer:

The rows tell you how many shells there are of the atom.

Answer:

Dimensional Analysis (also called Factor-Label Method or the Unit Factor Method) is a problem-solving method that uses the fact that any number or expression can be multiplied by one without changing its value. It is a useful technique.

Answer:

1.22 × 10^22 H atoms

Explanation:

From this question, TNT has the chemical formula: C-H5N306. The number of nitrogen atoms in the TNT substance is said to be 7.30 × 10^21 atoms.

The number of hydrogen atoms in the same TNT substance can be got using mole ratio. Based on the chemical formula, the mole ratio of hydrogen to nitrogen is 5:3 i.e. H5N3.

This means that;

Number of atoms of hydrogen = 5/3 of the number of atoms of nitrogen.

Hence, number of H atoms = 5/3 × 7.30 × 10^21

number of H atoms = (7.30 × 5/3) × 10^21

number of H atoms = (36.5/3) × 10^21

number of H atoms = 12.1666 × 10^21

number of H atoms = 1.2166 × 10^22 atoms.

Approximately, number of H atoms in TNT is 1.22 × 10^22 atoms.

Answer:

CCl₄

Explanation:

The molecule with a tetrahedral molecular geometry is CCl₄.

We know this according the valence shell electron pair repulsion theory.

To have a tetrahedral shape, a molecule must be made up of 4 bond pairs and no lone pairs.

This is clearly exhibited in the compound given;

 The central atom has 4 valence electrons which is completed bonded by 4 chlorine atom.

There is no lone pair but we have 4 bond pairs and a tetrahedral shape is formed.

Answer: No because a solution is a homogeneous MIXTURE of two or more substances. Water is a pure substance. It is made of hydrogen and oxygen, but shares none of their properties. So it’s pure.

Explanation:

Answer:

hydrogen atom but see the note below.

Explanation:

This is either the most common hydrogen ion or a hydrogen atom. It cannot be either of hydrogen's isotopes.

Answer:

483 nm corresponds to blue light hence the complex will appear orange.

Explanation:

Using the formula;

E= hc/λ

Where;

E = energy of the photon

h = Plank's constant (6.6*10^-34Js)

c = Speed of light (3*10^8 ms-1)

λ = wavelength

λ = hc/E

λ = 6.6*10^-34 * 3*10^8/4.10×10^−19

λ = 4.83 * 10^-7 or 483 nm

483 nm corresponds to blue light

Using the colour wheel approach, if a complex absorbs blue light, then it will appear orange.

Answer:

K2CrO4 (aq)

Explanation:

previous nect

Answer:

16 neutrons

Explanation:

now that protons are equal to electrons, there are 15 electrons. The mass is equal to 31.0, which is the ≡ of protons and ≡ neutrons added together. To find the number of neutrons, subtract the atomic # from the total mass #. 31-15=16 this would be equal to 16 now that the atomic has 31 and the mass is 15 subtract them ... you would get 16 neutrons inside the nucleus.

hope this helped ((((: if it did then please mark brainliest and have a wonderful day d:

Answer:

16

Explanation:

To find the neutrons, it's always mass-atomic number. Since the atomic number for an atom is always the protons, it's really mass-protons.

31-15=16

Explanation:

Given parameters:

Mass  = 9.5g

Volume  = 2.1cm³

Unknown:

What kind of substance is this = ?

Solution:

To determine the kind of substance given, we need to find its density from the given parameters.

The density of a substance can tell us about such body.

Density is an intensive property and it is the mass per unit volume.

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

Now insert the parameters and solve;

    Density  = [tex]\frac{9.5}{2.1}[/tex]  = 4.52g/cm³

The substance will most likely be a solid.

Answer:

237.8L of water would need to be added.

Explanation:

The first thing to do is to identify that the equation to be used is M1V1=M2V2. (This equation works because it turns everything into moles which can then be compared).

Then figure out what information you have and what is being found. In this case:

M1 = 54.7 M

V1 = 1092 mL = 1.092 L

M2 = 0.25 M

V2 = unknown

Then solve the equation for whatever you are trying to find.

M1V1=M2V2

V2=M1V1/M2

Now you need to plug everything in.

V2=(54.7M*1.091L)/0.25M

V2=238.93L

That means that the solution needs a volume of 238.7L to gain a molarity of 0.25M but the starting solution already had a volume of 1.092 L meaning that to find the amount of solvent that needs to be added you just subtract the starting volume by the volume that the solution needs to be.

238.93L - 1.091L = 237.8L

Therefore the answer is that 237.8L needs to be added to a 1.092L 54.7M NaCl solution to make the concentration 0.25M.

I hope this helps.  Let me know if anything is unclear.

Answer:

The epic emotional journey of a suburban African American family as they navigate love, forgiveness and coming together in the wake of a tragic loss.

Explanation:

hope thsi helps if so please brainliest

Merry Christmas

Answer:

Gas

Explanation:

Answer:?

Explanation: i'm confused with this and i know i should be writing this in comments but if you can explain me the question maybe i could help you

Answer:The elements in the first column of the Periodic Table (other than hydrogen) are known as Group 1A metals, or alkali metals. When you compare the chemical properties of these elements (lithium, sodium, potassium, rubidium, cesium, and francium), what you'll notice is that they are all remarkably similar.

Explanation:

Lithium, sodium, and potassium are the three elements from group number 1 of the periodic table that has similar chemical and physical properties, these group 1 metals are also known as alkali metals.

The total number of protons present in an atom is known as the atomic number of that atom. The atomic number has no correlation either with the number of neutrons or the number of electrons present inside an atom.

Group 1 metals, often known as alkali metals, are a trio of elements from the periodic table that have similar chemical and physical characteristics. They are lithium, sodium, and potassium.

Thus, Lithium, sodium, and potassium are the three elements from group number 1 of the periodic table that has similar chemical and physical properties.

To learn more about the atomic number from here, refer to the links;

brainly.com/question/14190064

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Answer:

Cell --> Tissues --> Organs ---> Organ System ---> Organism

Answer: I believe it’s the second one

(F)

Explanation:

Answer:

[Ar] 3d¹⁰ 4s² 4p³

Explanation:

so...... ur welcome