What does the atomic weight (mass number) of an element represent? ____________________________ .

v=293+523

v=816

this is the answer

thank you

Answer:

it's 8

Explanation:

the last group of the periodic table is group 8. so all elements in a group should have the same number of valency electrons

Answer:

943.82 ml

Explanation:

Assuming constant pressure

V1/T1 = V2/T2

T2 * V1/T1 = V2       ( T must be in K units)

(220 + 273.15) * 540 / (273.15 + 9) = 943.8 ml

To prepare 0.194 M potassium acetate, add 2.379895 g of potassium acetate to a 125 mL volumetric flask and fill with water to the mark.

Molarity (M) is the amount of a substance in a certain volume of solution. Molarity is defined as the moles of a solute per litres of a solution.

The following data were obtained from the question:

Molarity of potassium acetate = 0.194 M

Volume of solution = 125 mL

Mass of potassium acetate =?

Next, we shall convert 125 mL to L. This can be obtained as follow:

1000 mL = 1 L

Therefore,

125 mL = 0.125 L

Thus, 125 mL is equivalent to 0.125 L.

Next, we shall determine the number of moles of potassium acetate in the solution. This can be obtained as follow:

Molarity of potassium acetate = 0.194 M

Volume of solution = 0.125 L

Moles of potassium acetate =?

Molarity = [tex]\frac{mole}{Volume}[/tex]

Cross multiply

Mole of potassium acetate = 0.194 M × 0.125

Mole of potassium acetate = 0.02425 mole

Finally, we shall determine the mass of potassium acetate

Molar mass of potassium acetate= 98.14 g/mol

Mass of potassium acetate =?

Mole = [tex]\frac{mass}{Molar mass}[/tex]

Mass of potassium acetate =0.02425  × 98.14

Mass of potassium acetate = 2.379895 g

Thus, to prepare 0.194 M potassium acetate, add 2.379895 g of potassium acetate to a 125 mL volumetric flask and fill with water to the mark.

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Answer:

battery. you use it for your remotes. vinegar. you use vinegar for cooking of cleaning. nail polish remover. you use this for removing nail polish

Explanation:

Winter 4

Season when the northern hemisphere is tilted away from the sun.

Summer 2

Season when the northern hemisphere is tilted towards the sun.

Spring 1

Season when the northern hemisphere is neither tilted towards nor away from the sun; days getting longer and warmer.

Fall 3

Season in the northern hemisphere when the Earth is neither tilted towards nor away from the sun; days getting shorter and cooler.

When a strong acid such as HCl is added to the carbonic acid buffer system, more carbonic acid is formed.

A buffer system prevent the pH change and resist it when an acid or base is added to the solution.

A buffer system is prepared by weak acid or weak base and their salts. There are three types of buffer system present.

Thus, the correct option is b. More carbonic acid is formed.

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Answer:Seeds are great sources of fiber. They also contain healthy monounsaturated fats, polyunsaturated fats and many important vitamins, minerals and antioxidants. When consumed as part of a healthy diet, seeds can help reduce blood sugar, cholesterol and blood pressure

Explanation:

Answer:

Seeds grow plants wherever they fall is in the right condition and can be used as a sort of food for humans

Explanation:

Lewis acid and base are the chemical species that accept and donate pairs of electrons. Boron trifluoride, copper ion, and sulfur dioxide are lewis acids, and iodide ion and water are lewis bases.

Lewis acids are the chemical species that accept the nonbonding electron pair from other chemical species. Hence is an electron-pair acceptor. Boron trifluoride, copper ion, and sulfur dioxide are lewis acids as they can accept an electron to complete an octet.

Lewis bases are the chemical species that donate the non-bonding electron pair to the other chemical species. Hence is an electron-pair donor. Halogen or the iodide and water is a lewis base as it is an electron-rich species.

Therefore, water and iodide is lewis base.

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Answer:

Bubbles indicate change  

Explanation:

i don't know if i'm right but if im not its fine

Hope it helps<3

Answer:

X is an element in period 3 with two electrons in the outer shell

Answer:

Freezing point depression is a property of solutions where the solute lowers the normal freezing point of the solvent.

Explanation:

I think the answer is this for a better check mass- mass ratio in stoichiometry lesson

Answer:

If I understood correctly, your answer should be 0.64 grams

Explanation:

Answer:

I beileve it is NORTH KOREA!! XD actually D.

Explanation:

Balanced chemical equation for the reaction between sulfuric acid & solid aluminum hydroxide to form liquid water and a soluble salt is 3H₂SO₄ + 2Al(OH)₃  Al₂(SO₄)₃ + 6H₂O.

Balanced chemical equations are those in which all entities are present in same amount on both sides of the chemical equation.

Balanced chemical reaction for the given compounds will be shown as:

3H₂SO₄ + 2Al(OH)₃  Al₂(SO₄)₃ + 6H₂O

Above chemical equation is the balanced equation as all atoms are present in same amount on the left side as well as on the right side of the reaction.

Hence balanced equation is 3H₂SO₄ + 2Al(OH)₃  Al₂(SO₄)₃ + 6H₂O.

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Answer:

Compute the reaction rate to the nearest whole number using the formula below,

mass of tablet/volume of water

Reaction Rate = mas

reaction time

3°C Reaction time = 138.5 sec

Reaction rate = mg/l/sec

24°C Reaction time = 34,2 sec

Reaction rate = mg/L/sec

40°C Reaction time = 26.3 sec

Reaction rate = mg/L/sec

65°C Reaction time = 14.2 sec

Reaction rate = mg/L/sec

Explanation:

I hope my answer help

Answer:

#1 is 36 (138.5 seconds)

#2 is 146 (34.2 seconds)

#3 is 190 (26.3 seconds)

#4 352 (14.2 seconds)

#5 is 145 (34.5 seconds)

#6 is 173 (28.9 seconds)

#7 is 216 (23.1 seconds)

Explanation:

Edge, we may have different orders.

[tex]\sf\large \green{\underbrace{\red{Answer⋆}}}:[/tex]

0.250 moles

Explanation:

First we will convert quantity of solution into liters

[tex] \implies \sf 125 \: ml \times {10}^{ - 3} = 0.125 \: l[/tex]

Now we will use morality formula

[tex] \sf molarity = \frac{no \: of \: moles}{volume} \\ \\ \sf no \: of \: moles = molarity \times volume[/tex]

Here volume(quantity) = 0.125 l

AND no. of moles(given) = 2.0M

[tex] \sf \implies no \: of \: moles = 2 \times 0.125 \\ \\ \sf \implies no \: of \: moles = 0.250 \: moles \: of \: HCl[/tex]

[tex]~~~~~~w = \dfrac{SVM}{1000}\\\\\\\implies nM = \dfrac{SVM}{1000}\\\\\\\implies n= \dfrac{SV}{1000}\\\\\\\implies n = \dfrac{125 ~ \text{mL}\times 2.0~ \text{M}}{1000}\\\\\\\implies n = \dfrac{250}{1000}\\\\\\\implies n = 0.25~ \text{mol.}\\\\\text{The number of moles is 0.25.}[/tex]

The electronegativity of the element affects the ability of its compounds to dissolve in different solvents.

Electronegativity is a measure of an atom's ability to attract shared electrons to itself.

Polar bonds have a positive and negative side to them, and therefore can attract water dipoles and dissolve in water.

If the polarities of the solvent and solute match (both are polar or both are nonpolar), then the solute will probably dissolve.

If the polarities of the solvent and solute are different (one is polar, one is nonpolar), the solute probably won't dissolve.

Hence, option D is correct.

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The volume which is occupied by 0.445 mol of carbon dioxide at 397K and 973mmHg is 11.32 L.

Ideal gas equation will be represented as:

PV = nRT, where

P = pressure = 973 mmHg = 1.28 atm

V = volume = ?

n = moles = 0.445 mol

R = universal gas constant = 0.082 L.atm / K.mol

T = temperature = 397 K

On putting all these values, we get moles as:

V = (0.445)(0.082)(397) / (1.28) = 11.317 = 11.32 L

Hence required volume of gas is 11.32 L.

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Answer:

A !!

it a mix where everything is combined together

Take the cuttings from the trees and place them around in different enviornements, if the trees grow up to be the expected size in a different eviornement then the the scientists' claim is correct.

I didn't understand at first either, the question is worded a little strangly, but I believe this should answer the question that was asked.

Answer:

3.12 L

Explanation:

Given the R value that is supplied

      you will need to convert to atm from mm Hg    and C  to K

269 mm / 760 mm/atm = .354 atm

176 c = 449.15

PV = n RT

V = n RT / P    = .03 * .08206 * 449.15  / .354 = 3.12 L

The amount that is Left after 37.2 hr must be less than the original amount of K-42 initially present.

The term radioactivity has to do with the spontaneous disintegration of a substance.

To determine the mass of the K-42 that remains, we must have the half life of the isotope or the decay constant and both information are missing.

However, the amount that is Left after 37.2 hr must be less than the original amount of K-42 initially present.

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Answer:

50 kJ

Explanation:

Activation energy is the energy to go from reactants at 150  to   200 kJ

 = 50 kJ

Answer:

C. Condensation

Explanation:

When molecules release heat energy, it is called exothermic. In this case, condensation would be an example of this.

Answer: it is C condensation

Explanation: I took the quiz

Hope this helps

Hane a nice day

Could you mark me as branly if you could thank you :)

Answer:

Some important achievements of chemistry includes discovery of oxygen ;Atomic Theory; Atoms Combine Into Molecules ;Synthesis of Urea; Chemical Structure ; Periodic Table of the Elements; Electricity Transforms Chemicals ; The Electron etc.

Chemistry is a field of science which deals with the chemicals present in laboratory or in our environment o related to human body also.

There are main 3 branches of chemistry that is organic and inorganic and physical chemistry some others are too like analytical chemistry ,industrial chemistry , pharmaceutical chemistry.

Organic chemistry deals with the carbon compounds and hydrogen compound inorganic chemistry deals with the elements of periodic table and pharmaceutical makes medicines for human health care. The reasons  for people to pursue discoveries in chemistry because it is the most important part of  daily life and related to the human health too.

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The complete question

Mention some important achievements of chemistry