please help me i will give brain list​

Answer:

a. chemical change

Explanation:

A chemical change can cause an odor, however a physical change cannot, and the use of thermal energy will only make an object colder, not give it an odor.

Answer:

Chemical reaction

Explanation:

It's creating a whole other substance

The chemist weigh out 35.51 g Na2SO4

Given

0.250 moles of Na2SO4

Required

weight of Na2SO4

Solution

A mole is a number of particles(atoms, molecules, ions)  in a substance

This refers to the atomic total of the 12 gr C-12  which is equal to 6.02.10²³, so 1 mole = 6.02.10²³ particles  

Moles of a substance can also be determined from its molecular weight

[tex]\tt mol=\dfrac{mass}{MW}[/tex]

For 0.250 moles of Na2SO4, mass =

[tex]\tt mass=mol\times MW\\\\mass=0.25\times 142,04 g/mol\\\\mass=35.51~g[/tex]

Answer:

3.128 m/s^2

Explanation:

Acceleration is the change in velocity over the change in time. Final velocity is 42 mph and initial velocity is 0 mph, but we need to convert these values to meters per second (m/s).

To do that, we divide 42 by 2.237 and the result is 18.77.

Now we can calculate the change in velocity: 18.77 - 0 = 18.77 m/s.

Now we need the change in time: 6 s is the elapsed time, 0 s in the starting time. So 6 s - 0 s = 6 s.

Now we divide 18.77 by 6 s and obtain the answer, which is:

18.77 m/s ÷ 6 s = 3.128 m/s^2

The amplitude is greater for both

The frequency is for wave two

Explanation:

Answer: Servsafe 9

Explanation:

Remove food from the surface

clean the surface

rinse the surface

sanitize the surface

allow the surface to air dry

Cups and glasses are taking too long to air dry. This could be caused by the ventilation system not working properly. The correct option is D.

A ventilation system is a mechanical device that is normally created and built to supply airflow into and out of a structure or other enclosed space. Because air is provided by a functioning ventilation system, moisture on surfaces like cups and glasses can dry more quickly.

It is possible to describe air-drying as a technique or process for removing moisture from surfaces using either heated, forceful, or dry air. Therefore, air drying aids in making the surface of goods like cups and glasses dry, or free of moisture.

Thus, the correct option is D. The ventilation system not working properly.

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The question is incomplete. Your most probably complete question is given below:

A. Incorrect timing of the wash cycle.

B. An improper use of chemical sanitizer.

C. The water temperature being too high.

D. The ventilation system not working properly.

Answer:

1.12 moles of potassium

6.76x10²³ atoms of potassium

Explanation:

In order to convert g of potassium to moles, we need to use its molar mass (which we can find via the periodic table):

Then, to convert moles into atoms, we use Avogadro's number (6.023x10²³ atoms per mole):

The seedlings exerted an upward pushing force on the soil explains why the

seeds emerged from the soil.

Bob watered the soil in which the seed absorbs the water through the coat ,

the seed coat and embryo begins to enlarge and emerge from the soil.

The hydrated enzymes become active thereby increasing metabolic

activities and energy production which is needed for the growth of the plant.

The energy helps the seed exert an upward force on the soil.

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Answer:

12.3 L

Explanation:

Now we have that the rate of diffusion of the saturated hydrocarbon is R1

Rate of diffusion of sulphur dioxide is R2

Molar mass of hydrocarbon is M1

Molar mass of sulphur dioxide is 64 gmol-1

From Graham's law;

R1/R2 = √64/M1

2/1 =√64/M1

(2/1)^2 = (√64/M1)^2

4/1 = 64/M1

4M1 =64

M1 = 16

To obtain the number of moles of the gas;

(n*12) + (2n + 2) 1 = 16

12n + 2n + 2 = 16

14n + 2 = 16

14n = 16 - 2

n = 14/14

n = 1

Hence the hydrocarbon is CH4

Volume occupied by CH4 at STP = 22.4 L

Hence;

P1 = 1 atm

T1 = 273 K

V1 = 22.4 L

T2 = 300 K

P2 = 2 atm

V2 = ?

P1V1/T1 = P2V2/T2

P1V1T2 = P2V2T1

V2 = P1V1T2/P2T1

V2 = 1 * 22.4 * 300/2 * 273

V2 = 12.3 L

The volume occupied by the hydrocarbon at 27 °C and 2 atm is 12.31 L

Let the hydrocarbon be initially at standard temperature and pressure (STP)

Thus, we can obtain the new volume of the hydrocarbon by using the combined gas equation as illustrated below:

P₁V₁ / T₁ = P₂V₂ / T₂

(1 × 22.4) / 273 = (2 × V₂) / 300

22.4 / 273 = (2 × V₂) / 300

Cross multiply

273 × 2 × V₂ = 22.4 × 300

546 × V₂ = 6720

Divide both side by 546

V₂ = 6720 / 546

V₂ = 12.31 L

Thus, the volume occupied by the hydrocarbon at 27 °C and 2 atm is 12.31 L

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Answer:

(B) -125 kJ

Explanation:

Going by the First Law of Thermodynamics it states that"

"A system can do work and increase it's internal energy provided we supply heat."

ΔU= q+w-----------1

where U= the internal heat

           q= the quantity of heat added or removed from the system

            w= the work done

Given

ΔU= 250kJ

q= 375kJ

from equation 1 make w subject of the formula we have

w= ΔU-q

w= 250-350

w= -125kJ

Answer:

This is not a viable question.

Explanation:

Answer:

Chemistry deals with matter, and there is a tremendous variety of matter in the universe. The behavior of matter depends on the type of elements that are present and on the structure of those elements—how they are connected to make a molecule. In this exercise, you will evaluate some representative models to develop the rules used to classify a compound, to predict the formula of a compound, and to name the compound. This exercise is just the beginning of the work needed to be done to master the rules of writing formulas and nomenclature. Your textbook has tables of the names and formulas of common cations and anions, and discusses the rules of nomenclature in detail. You will need to spend some time with this material, as the formal rules of nomenclature may not be presented in lecture, although they will certainly be used in discussions of Lewis structures and reaction chemistry.

Explanation:

In a covalent compound, valence electrons are shared between the two atoms in the bond. These can be evenly shared (covalent bond) or unevenly shared (polar covalent bond). In an ionic bond, electrons are localized to one of the atoms (giving it an overall negative charge), while the other atom has an overall positive charge. The difference in electronegativity between the two atoms in the bond can help predict whether the bond is likely to be ionic, covalent, or polar covalent, as can the type of atoms involved (metals or non-metals). A bond with two identical atoms is always pure covalent, while a covalent bond with two different atoms is likely to be polar covalent.

Answer:

Red and Orange

Explanation:

Complementary colors are those colours located across from each other on a color wheel. If we look at the colour wheel attached to this answer, we will see various complementary colours shown.

A good look at the attached colour wheel reveals that blue Cu2+ ions absorbs light around the red and orange portions of the visible spectrum.

Use this formula PV=nRT

Rearrange formula , question want V ,so

V=nRT/P

given

P= 3.00 atm

n=0.450 moles

R is ideal gas constant = 0.08206 L atm mol-¹K-¹

T in Kelvin so , (75 + 273)= 348 Kelvin (K)

Then insert all this information given with that rearranged formula V=nRT/P

Answer:

A

Explanation:

common sense

Answer:

are you good at sailing A.

Answer:

I think it's true. But I'm not sure

Answer:

True

Explanation:

Answer:

The enthalpy of neutralization and its relation to esterification​ is explained below in details.

Explanation:

The conventional enthalpy variation of neutralization is the enthalpy exchange when extracts of an acid and an alkali respond together under conventional circumstances to generate 1 mole of water. Remark that the enthalpy change of neutralization is always estimated per mole of water produced.

Answer:

Melting point

Explanation:

it's constant temperature at which the bonds of a solid Crystal lattice are broken down by overcoming the attractive forces converting it to liquid

Answer:

Hydrogen

Explanation:

Helium has an atomic number Z = 2, that is, it has 2 protons. Since it is electrically neutral it also has 2 electrons. Thus, the electron configuration of helium is 1s².

Hydrogen has an atomic number Z = 1, that is, it has 1 proton. Since it is electrically neutral it also has 1 electron. Thus, the electron configuration of hydrogen is 1s¹.

If hydrogen gains a single extra electron to form H¹⁻, it acquires the same electron configuration than helium.

The complete question is attached to this answer

Answer:

2.75 * 10^-5 m

Explanation:

The energy of the absorbed photon = ΔE

ΔE = - Ry (1/n^2 final - 1/n^2initial)

Given that Ry = 2.18 *10^-18 J

nfinal = 9

ninitial =8

ΔE = - 2.18 *10^-18 (1/9^2- 1/8^2)

ΔE = - 2.18 *10^-18 (0.0123 - 0.0156)

ΔE = 7.194 * 10^-21 J

But

ΔE =hc/λ

h = 6.6 *10^-34Js

c= 3 * 10^8 ms-1

λ= the unknown

λ= hc/ΔE

λ= 6.6 *10^-34 * 3 * 10^8/ 7.194 * 10^-21

λ= 2.75 * 10^-5 m

Answer:

-1.82 °C

Explanation:

Step 1: Given data

Step 2: Calculate the molality of the solution

We will use the following expression.

m = mass of solute / molar mass of solute × kg of solvent

m = 33.9 g / 58.44 g/mol × 0.578 kg

m = 1.00 m

Step 3: Calculate the freezing point depression (ΔT)

The freezing point depression is a colligative property that, for a non-dissociated solute, can be calculated using the following expression:

ΔT = Kb × m

ΔT = -1.82 °C/m × 1.00 m

ΔT = -1.82 °C

Answer:

where are the statements?

Explanation:

Explanation:

Mole ratio of Ethane to Oxygen = 2 : 7

Moles of O2 needed = 24 moles * (7/2) = 84 moles.

Moles are the ratio of the mass and the molar mass of the substance. 84 moles of oxygen are needed to react with Ethane.

Moles are the unit of the measurement of small entities like molecules, atoms, or particles.

The reaction is shown as:

[tex]\rm 2C_{2}H_{6} +7O_{2} \rightarrow 4CO_{2} + 6H_{2}O[/tex]

From the reaction, it can be said that the mole ratio of ethane [tex](\rm C_{2}H_{6})[/tex] and oxygen [tex](\rm O_{2})[/tex] is 2:7.

Then moles of oxygen will be,

[tex]24 \times \dfrac{7}{2} = 84[/tex]

Therefore, 84 moles of oxygen are needed to react with 24 moles of ethane.

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Answer:

Reflecting telescopes take up less space, is the suitable answer.

Answer:

B, or 2: Reflecting telescopes produce clearer images.

Explanation:

Took the test

Answer: Chemical energy

Explanation: In this case plants convert light energy (1) into chemical energy, (in molecular bonds), through a process known as photosynthesis. Most of this energy is stored in compounds called carbohydrates. The plants convert a tiny amount of the light they receive into food energy.

Answer:

chemical energy

In this case plants convert light energy into chemical energy, (in molecular bonds), through a process known as photosynthesis. Most of this energy is stored in compounds called carbohydrates. The plants convert a tiny amount of the light they receive into food energy.

Explanation:

Pieces of DNA that pass genetic traits from parent to offspring are called as gene.

DNA is a hereditary material  which is present in human beings as well as all other living organisms.  Every cell which is present in an organism's body has DNA  which is the same. Most of the DNA is situated in the cell's nucleus  and small amount of it can be found in the cell's mitochondria as well.

Information which is stored in DNA is stored as codes made up of four chemical bases namely, adenine, thymine , cytosine and guanine.Human DNA consists of 3 billion bases .The order of the bases determines information which is required for building and maintaining an organism.

DNA bases are capable of pairing up with each other. Adenine pairs with thymine and guanine pairs up with cytosine .Each base is also attached to a sugar molecule  and a phosphate group. A base, phosphate  sugar are together called as nucleotides.

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Answer:

Due to "Common ion effect".

Explanation:

Lead chloride and Silver chloride have an ion in common which is Cl-, when these two solutions are dissolved, more chloride reacts with lead which shifts equilibrium position to the right hence precipitating out.

Answer:

84.01 g/mol

Explanation:

Look at your periodic table for the atomic mass for Na, H, and C, and O

Na = 22.99

H = 1.01

C = 12.01

O = 16.00

They are three oxygen atoms. So 16(3) = 48

Now do basic math.

22.99 + 1.01 + 12.01 + 16.00(3) = 84.01 g/mol.

Literally found this in a YouTuube video lol. Hope it helped doe!

The molar mass of sodium bicarbonate (NaHCO₃) is approximately 84.01 grams per mole (g/mol).

To calculate the molar mass of sodium bicarbonate (NaHCO₃), you need to sum the atomic masses of all the atoms in the chemical formula.

The atomic masses:

Sodium (Na) = 22.99 g/mol

Hydrogen (H) = 1.01 g/mol

Carbon (C) = 12.01 g/mol

Oxygen (O) = 16.00 g/mol

Now, let's calculate the molar mass of NaHCO₃:

Molar mass of NaHCO₃ = (1 * Na) + (1 * H) + (1 * C) + (3 * O)

Molar mass of NaHCO₃ = (1 * 22.99 g/mol) + (1 * 1.01 g/mol) + (1 * 12.01 g/mol) + (3 * 16.00 g/mol)

Molar mass of NaHCO₃ = 22.99 g/mol + 1.01 g/mol + 12.01 g/mol + 48.00 g/mol

Molar mass of NaHCO₃ = 84.01 g/mol

Therefore, the molar mass of sodium bicarbonate (NaHCO₃) is approximately 84.01 grams per mole (g/mol).

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