How do I find the average atomic weight of an element

Answers

Answer 1

Answer:

To calculate the average atomic mass, multiply the fraction by the mass number for each isotope, then add them together.

hope this helps <3

Answer 2
It is calculated by summing the masses of the element’s isotopes

Related Questions

please help!!!!!!!!!​

Answers

Answer

At the crust

Explanation:

Mantle is far away from it unless its in a ocean.

Answer:

A mountain would form on the continental crust

Explanation:

Typically, a convergent plate boundary—such as the one between the Indian Plate and the Eurasian Plate—forms towering mountain ranges, like the Himalaya, as Earth’s crust is crumpled and pushed upward.

Formula for gallium peroxide

Answers

Answer:

Ga₂O

Explanation:

5. The point at which the relative humidity reaches 100% is the
and (2 points)
the air can hold no more water vapor.

Answers

The dew point is the temperature the air needs to be cooled to (at constant pressure) in order to achieve a relative humidity (RH) of 100%. At this point the air cannot hold more water in the gas form.

Answer:

ii cud givee uu an explanation for understandment for help if still don't understand im sowwyy thenn.

Explanation:

relative humidity is related to the partial pressure of water vapor in the air at 100% humidity the partial pressure is equal to the vapor pressure and no more water can enter the vapor phase.

he specific rate constant, k, for the following first-order
reaction is 9.16 x 10-3
s
-1 at 0.0°C. The activation energy of
this reaction is 88.0 kJ/mol. Determine the value of k at
2.0°C.
N2O5  NO2 + NO3

Answers

Hope this helps. Thanks

Cotton and coir are the types of ___________fibres.

Answers

Answer:

natural

Explanation:

hope this helps you!!

mark as brainliest please

Answer:

seed fibers

Explanation:

since they're harvested separately from their seed

Which of the following statements best describes chemical equilibrium?

Answers

Answer:

A state in which the concentrations of all the reactants and products remain constant with time

Explanation:

The statement which best describes chemical equilibrium is that the concentrations of all the reactants and products remain constant with time.

What is Equilibrium?

This is the situation in an object in which two or more forces or factors counter-influences because of them being constant.

In this scenario, the concentrations of all the reactants and products is constant which depicts the right choice.

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Question 25 of 30
Which statement best describes what happens when thermal energy of the
air around a fire is transferred to the surrounding air?
O A. The thermal energy is spread out by the surrounding air.
O B. The thermal energy is destroyed as it changes to chemical energy.
C. The thermal energy is destroyed over time.
ОО
D. The thermal energy changes to chemical energy.
SUBMIT

Answers

The answer would be a :)

Answer: The thermal energy is spread out by the surrounding air.

Explanation:

got it right on test

0.250 moles of NaCl is dissolved in 0.850 L of solution. What is the molar concentration?

Answers

Considering the definition of molarity, the molar concentration is 0.294 [tex]\frac{moles}{liter}[/tex].

Molarity reflects the concentration of a solution indicating the number of moles of solute that are dissolved in a given volume.

The molarity of a solution is calculated by dividing the moles of the solute by the volume of the solution:

[tex]molarity=\frac{amount of moles of solute}{volume}[/tex]

Molarity is expressed in units [tex]\frac{moles}{liter}[/tex].

In this case, you know:

amount of moles of solute= 0.250 molesvolume= 0.850 L

Replacing in the definition of molarity:

[tex]molarity=\frac{0.250 moles}{0.850 L}[/tex]

Solving:

molarity= 0.294 [tex]\frac{moles}{liter}[/tex]

Finally, the molar concentration is 0.294 [tex]\frac{moles}{liter}[/tex].

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Who is most likely associated with the quote below?

“Nothing exists except atoms and empty space; everything else is opinion."

А: Democritus
B: Aristotle
C: Thales
D: Epicurus

Answers

Answer:

democritus

Explanation:

i looked it up

Zinc chloride can be made from the reaction between zinc oxide and hydrochloric acid. Describe a laboratory method to produce pure dry  crystals of zinc chloride. (6 marks)

Suggest an alternative to zinc oxide that could react with hydrochloric acid to give you the desirable product.(1 mark)

Answers

Crystallization, followed by filtration to remove excess solution, followed by drying on a watch glass or in a warm oven, can yield pure dry crystals of zinc chloride.

What is crystallization?

Crystallization is defined as the formation of a solid in which the atoms or molecules are highly organized into a structure known as a crystal.

It can also be defined as a natural process that occurs when materials solidify from a liquid or precipitate from a liquid or gas.

There are basically three types of crystallization.

Evaporative crystallizationCooling crystallization from solution or the meltReactive crystallization or precipitation

Filtration is defined as the process of removing solid particles from a liquid or gaseous fluid by using a filter medium that allows the fluid to pass through but retains the solid particles.

Zinc oxide that could react with hydrochloric acid to give you the desirable product because acid is a neutralizing base, the reaction of hydrochloric acid with zinc oxide to form zinc chloride and water is a neutralization reaction .

Thus, crystallization, followed by filtration to remove excess solution, followed by drying on a watch glass or in a warm oven, can yield pure dry crystals of zinc chloride.

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If a steam reforming line processes methane at a temperature of
725.0°C and a pressure of 12.00 atm, what is the volume (in L) that
20.0 moles of methane would occupy in the reactor?

Answers

Answer:

ideal gas law. PV=nRT

Explanation:

pressure x volume = #moles x R (constant of 8.31) x temp

first one is the answer

Answers

Answer:

but where is yr question????

Answer:

Where is your question bro

Find the sum of coefficients for all reactants and products.

CuBr2 + H3PO4 ⇨ Cu3(PO4)2 + HBr

Answers

3CuBr2 + 2H3PO4 –> Cu3(PO4) + 6HBr

The sum of coefficients for all reactants and products of given reaction is 12.

[tex]CuBr_{2} + H_{3}PO_{4}[/tex]⇨ [tex]Cu_{3} (PO_{4})_{2} + HBr[/tex]

For finding coefficients each molecules in reactant and product, first we have to balanced the given chemical equation.

What is balanced chemical equation?

The chemical equation in which number of atoms for each elements and total charges is same in both side, reactant as well as product in a reaction.

Example: Let the unbalanced chemical equation is,

[tex]CuBr_{2} + H_{3}PO_{4}[/tex]⇨ [tex]Cu_{3} (PO_{4})_{2} + HBr[/tex]

So, the balanced chemical equation become.

[tex]3CuBr_{2} + 2H_{3}PO_{4}[/tex] ⇨ [tex]Cu_{3} (PO_{4})_{2} +6 HBr[/tex]

        Reactant                   Product

The number placed prior to the each molecules is called coefficient of reactant and product.

So, the total coefficient for reactant and product are 3 + 2 + 1 + 6 = 12.

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Classify the molecules based on whether the molecule has a standard enthalpy of formation, AH;, equal to 0. Assume all
conditions are at standard pressure and temperature (STP).

Answers

The standard enthalpy of formation of substance in its standard state is zero.

Enthalpy is defined as a thermodynamic quantity that describes the energy of a system. For substances in their standard state, the enthalpy of formation is zero.

The standard state of a substance is defined as the state in which it is found under standard conditions.  The following substances has their standard ethalpy of formation as zero or not zero;

Zero enthalpy of formation           Non zero enthalpy of formation

Cl2(g)                                                     I2(s)

Br(g)                                                       Br2(l)

I2(g)                                                       Br2(s)

Hg(l)                                                       Hg(s)

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If you had excess chlorine, how many moles of aluminum chloride could be produced from 12.0g of aluminum

Answers

Answer:

Hence, 0.455 mol of aluminum chloride could be produced from 12.0 grams of aluminum.

Explanation:

Given data:

•Mass of aluminum is 12.0 grams.

To find:

•Number of moles of aluminum chloride produced from Al.

The given reaction is as follows:

2A1+ 3Cl₂ → 2AlCl3

First, we have to find the number of moles of aluminum by the relation given below:

n = m M;

Where:

•n is the number of moles.

•m is the mass in grams.

•M is the molar mass in g/mol.

The molar mass of Al is 26.98 g/mol. Substitute the values in above equation to obtain the number of moles of aluminium as follows:

n = (12.0g)/(26.98g /mol)

= 0.445 mol

From the reaction stoichiometry, we can see that 2 moles of Al forms 2 moles of aluminium chloride (A1C13). This means, the number of moles of Al and AlCl3 is equal.

So, 0.445 mol Al will give 0.455 mol AlC13.

Drawing Conclusions Why is it important to have such a detailed report on the economy? How does it help the president and Congress make decisions about taxes and expenditures

Answers

A detail report is very important for better decisions of President about economy.

It is very important to have such a detailed report on the economy because it helps the president as well as Congress to make better decisions about the imposing of taxes. It greatly helps and provides all information to the president and Congress so that they make better decisions about taxes and expenditures.

Without this detailed report, the Congress can't take right decisions about taxes and economy of the country so we can conclude that detail report is very important for better decisions of president about economy.

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WILL GIVE BRAINLIEST AND 20 POINTS!
Calculate the volume in milliliters of a solution required to provide 2.14 g o sodium chloride from a 0.930 M solution.

Answers

Answer:

Step 1 of 3

Here we have to calculate the volume of the solution in mL.

(a) 2.14 g of sodium chloride from a 0.270 M solution

We can calculate the volume of a solution from its molarity. It is known that the molarity of a solution can be calculated as follows,

Molarity = 

Hence volume of solution = 

Here it has been given that,

Mass of NaCl = 2.14 g

Molarity = 0.270 M

Molecular weight of NaCl = 58.44 g/mol

In order to calculate the volume, 1st we have to find out the number of moles,

Number of moles of NaCl = 

                                     =     = 0.03662 mol of NaCl

Now the volume can be calculated as,

volume of solution = 

               =    = 0.136 L or 136 mL solution

Hence the volume of NaCl is found to be 136 mL.

Daje 25pkt bo tylko tyle mam :(( pomoże ktoś?

Answers

Answer:

brak syna 25 punto, syn 13

Explanation:

How could the AX3 molecular structure (one central atom with three bonded atoms) be non-polar even with bond dipoles present?

options:

1. If there were no lone pairs on the central atom

2. If there were one lone pair on the central atom

3. If there were two lone pairs on the central atom

4. If there were three lone pairs on the central atom

Answers

The AX3 molecular structure (one central atom with three bonded atoms) can be non-polar even with bond dipoles present  If there were no lone pairs on the central atom. Option 1 is correct.

The molecular structure or shape is a 3-D pattern showing the arrangement of atoms of a molecule.

The molecular structure of AX3 is said to be composed of a central atom connected and bounded to three atoms which are equally spaced at an angle of 120° towards one another. It has a shape of trigonal planar and its sp² hybridized that does not have any lone pair.

The polarity of a molecule or a compound has to do with the presence of lone pair in the central atom. Since AX3 has no lone pair of electrons in its central atom it is said to be non-polar.

Example of compounds that exhibit AX3 with no lone pair is: BF₃ and CO₃²⁻

Therefore, we can conclude that we've understood what is molecular structure and how to identify the molecular structures that are polar and non-polar in nature.

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Change in oxidation number in zn is

Answers

Answer:

Equalize the changes in oxidation number Each Zn atom has lost two electrons, and each H atom has gained one electron. You need 2 atoms of H for every 1 atom of Zn. This gives us total changes of +2 and -2.

Explanation:

Hope this helps :)

pls make brainliest :P

And have an amazing day <3

What characterizes a homogeneous mixture?
A. The mixture settles out when left standing.
B. The substances are evenly distributed throughout.
O C. The mixture has different consistencies.
D. The substances are identifiable in the mixture.

Answers

Answer:

D. The substances are evenly distributed throughout.

need answers pls!! Multiple choice

Answers

D ..,…,,..,,..,::,,,.,

Answer:

BONJOUR.

CHEMICAL CHANGE ARE THOSE THAT FORM A NEW SUBSTANCE

PHYSICAL CHANGE ARE THOSE THAT DOESN'T FORM A NEW SUBSTANCE.

OPTION D IS THE ANSWER

I HOPE IT IS HELPFUL.

MERCI

A 17.5 mL portion of a 0.1050 M Na2CO3 solution is added to 46.0 mL of 0.1250 M NaCl. What is the concentration of sodium ion in the final solution?

Answers

The sodium ion concentration in the solution of 17.5 mL of 0.1050 M Na₂CO₃ and 46.0 mL of 0.1250 M NaCl is 0.148 M.

To find the Na⁺ concentration in the final solution, we need to find the number of moles of the ion in the Na₂CO₃ and NaCl solutions and the volume of the final solution.  

[tex] C_{Na^{+}} = \frac{n_{t}}{V_{t}} [/tex]  (1)

Where:

[tex] n_{t} [/tex]: is the total number of moles of Na⁺

[tex] V_{t} [/tex]: is the volume of the final solution

The number of moles of Na⁺ in the Na₂CO₃ solution

The number of moles of Na₂CO₃ can be calculated as follows:

[tex] n_{Na_{2}CO_{3}} = C_{Na_{2}CO_{3}}*V_{Na_{2}CO_{3}} [/tex]

Where:

[tex] C_{Na_{2}CO_{3}} [/tex]: is the concentration = 0.1050 mol/L

[tex] V_{Na_{2}CO_{3}} [/tex]: is the volume = 17.5 mL = 0.0175 L

[tex] n_{Na_{2}CO_{3}} = 0.1050 mol/L*0.0175 L = 1.84 \cdot 10^{-3} \:moles [/tex]

We can find the number of moles of Na⁺ knowing that in 1 mol of Na₂CO₃ we have 2 moles of Na⁺.

[tex] n_{Na^{+}} = \frac{2 \:mol\: Na^{+}}{1\:mol \:Na_{2}CO_{3}}*mol \:Na_{2}CO_{3} = \frac{2 \:mol\: Na^{+}}{1\:mol \:Na_{2}CO_{3}}*1.84 \cdot 10^{-3} \:moles = 3.68 \cdot 10^{-3} \:moles [/tex]

The number of moles of Na⁺ in the NaCl solution

The number of moles of Na⁺ in the NaCl solution is:

[tex] n_{NaCl} = C_{NaCl}*V_{NaCl} = 0.1250 mol/L*0.046 L = 5.75 \cdot 10^{-3} \:moles [/tex]

In 1 mol of NaCl we have 1 mol of Na⁺, so the number of moles of Na⁺ in the NaCl solution is 5.75x10⁻³ moles.

Total number of moles of Na⁺

The total number of moles of Na⁺ in the final solution can be calculated as follows

[tex] n_{t} = n_{{Na^{+}}_{Na_{2}CO_{3}}} + n_{{Na^{+}}_{NaCl}} = 3.68 \cdot 10^{-3} \:moles + 5.75 \cdot 10^{-3} \:moles = 9.43 \cdot 10^{-3} moles [/tex]

Hence, the number of moles of Na⁺ in the final solution is 9.43x10⁻³ moles.

The volume of the final solution

The volume of the final solution is given by:

[tex] V_{t} = V_{Na_{2}CO_{3}} + V_{NaCl} = 0.0175 L + 0.046 L = 0.0635 L [/tex]

Concentration of Na⁺ in the final solution

The concentration of Na⁺ in the final solution is (eq 1):

[tex] C_{Na^{+}} = \frac{n_{t}}{V_{t}} = \frac{9.43 \cdot 10^{-3} moles}{0.0635 L} = 0.148 mol/L [/tex]

Therefore, the concentration of sodium ions in the final solution is 0.148 M.

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Consider the combustion of methane, CH4 :
Suppose 2.8 mole of methane are allowed to react with 5.0 mole of oxygen.
How many grams of CO2 Can be made from this reaction?
(your answer should have three significant figures). Do not include the unit in your answer.
CHA
+
202
CO2
+ 2H20

Answers

Answer:

CH4+3/2O2⇒CO2+2H2O

mCO2=2.8*44=123.2

Explanation:

Buffer #1: 0.15 M HF(aq) and 0.10 M NaF(aq)
Buffer #2: 0.090 M HF(aq) and 0.060 M NaF(aq)
Fill in the following sentence:
The pH values of Buffers #1 and #2 are _______, and the buffering capacity of Buffer #1 is _______ than that of Buffer #2.

a) unequal; higher
b) equal; lower
c) unequal; lower
d) equal; higher

Answers

Buffer #1: 0.15 M HF(aq) and 0.10 M NaF(aq)   Buffer #2: 0.090 M HF(aq) and 0.060 M NaF(aq). The pH values of Buffers #1 and #2 are equal, and the buffering capacity of Buffer #1 is higher than that of Buffer #2.

A buffer is a solution that is capable of withstanding changes in pH caused by the introduction of acid or base substances. It may neutralize tiny quantities of additional acid or base, allowing the pH of the solution to remain reasonably constant.

For buffer 1;

[HF] = 0.15 M [NaF] = 0.10 M

Under Standard Conditions, Ka(acid dissociation constant) for HF = 3.5 × 10⁻⁴

pKa = -log Ka

pKa = -log (3.5 × 10⁻⁴)

pKa = 3.454

The formula for calculating the buffer value can be represented by:

[tex]\mathbf{pH = pKa + log \dfrac{([A^+])}{([HA])}}[/tex]

[tex]\mathbf{pH = 3.454 + log \Big(\dfrac{0.10}{0.15}}\Big)[/tex]

pH = 3.2779

For Buffer 2;

[HF] = 0.090 M [NaF] = 0.060 M

[tex]\mathbf{pH = 3.454 + log \Big(\dfrac{0.06}{0.09}}\Big)[/tex]

pH = 3.2779

We can see that the pH of buffer 1 is equivalent to the pH of buffer 2.

Buffer capacity measures a solution's capacity to endure pH fluctuations by either accepting or detaching H+ and OH- ions.

For Buffer 1:

The buffer capacity can be expressed by using the formula:

[tex]\mathbf{\beta = \dfrac{2.3 \ Ka [H^+] [C]}{(Ka+ [HA])^2}}[/tex]

where;

C = total concentration of buffer components i.e.  [HA] + [A⁻]

[tex]\mathbf{\beta = \dfrac{2.3 \ \times 3.5 \times 10^{-4} \times (0.15) (0.15 \times 2)}{(3.5 \times 10^{-4} + (0.15)^2 }}[/tex]

[tex]\mathbf{\beta = \dfrac{3.6225 \times 10^{-5}}{0.02260}}[/tex]

[tex]\mathbf{\beta = 0.0016}[/tex]

For Buffer 2:

[tex]\mathbf{\beta = \dfrac{2.3 \ \times 3.5 \times 10^{-4} \times (0.09) (0.09 \times 2)}{(3.5 \times 10^{-4} + (0.09)^2 }}[/tex]

[tex]\mathbf{\beta = \dfrac{1.3041 \times 10^{-5}}{0.008163}}[/tex]

[tex]\mathbf{\beta = 0.00159}[/tex]

Therefore, we can conclude that the pH values of Buffers #1 and #2 are equal, and the buffering capacity of Buffer #1 is higher than that of Buffer #2.

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which ionic equation represents the reaction taking place at anode during the electrolysis of molten aluminium oxide?​

Answers

Explanation:

at the Anode, Oxide ions lose electrons and produce Oxygen gas

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What makes physical change a physical change and a chemical change a chemical change

Answers

A physical change is any change in a substances form that does not change its chemical makeup. Examples of physical changes are breaking a stick or melting ice. A chemical change occurs when atoms of a substance are rearranged, and the bonds between the atoms are broken or formed. HOPE THIS HELPS!!

Answer:

A physical change is reversible and the changes made are only physical (smell, physical state, volume, etc) and most importantly no new substance is formed. In a chemical change, a new substance is formed, the chemical properties are changed, and it's permanent.

Learning Task 3 Directions: Below are description of tools that need maintenance. Give the immediate maintenance procedure that should be done. Write your answers on a separate sheet of paper.

Preventive Maintenance Task of Tools and Equipment Description
1. a rake with wet wooden handle
2. a filler covered with sticky plant sap
3. clogged air filter of a chain saw
4. uncoiled garden hose
5. a wheelbarrow that won't roll​

ANSWER:
1.
2.
3.
4.
5.

Answers

Mi información y fotosíntesis

The volume between the 50.00 mark and the valve of a buret is 5.58 . The buret reading of an upside down buret containing a pocket of hydrogen gas is 31.15 mL. What is the total volume of hydrogen in the buret?

Answers

We have that for the Question ,it can be said that The total volume of hydrogen gas is

Vt=24.43ml

From the question we are told

The volume between the 50.00 mark and the valve of a buret is 5.58 . The buret reading of an upside down buret containing a pocket of hydrogen gas is 31.15 mL. What is the total volume of hydrogen in the buret?

Generally

With the buret divided into three

The value section the middle and the top

With hydrogen gas contained in the middle and value area

We have

Volume of middle

Vm=(50-31.15)

Vm=18.85ml

For Valve area

Vv=5.58ml

Therefore

The total volume of hydrogen gas is

Vt=Vm+Vv

Vt=18.85+5.58

Vt=24.43ml

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how has the model of an atom changed overtime?​

Answers

Answer:

This atomic model has changed over time. Scientists used the model to make predictions. Sometimes the results of their experiments were a surprise and they did not fit with the existing model. Scientists changed the model so that it could explain the new evidence.

Explanation:

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