Define valence electrons.

Answers

Answer 1

Answer:

Electrons on the outermost shell of an atom. They are responsible for the chemical properties of an atom.


Related Questions

You have a sealed 2 liter flask that contains nothing but water and carbon dioxide. The flask is half-filled with liquid water, has a temperature of 25°c, and the overall pressure within the flask is 0. 1 atm. How many moles of co2 are in the flask? at this temperature, you may take the kh value for co2 as 0. 033 m / atm.

Answers

In this exercise we want to calculate the amount of moles, so this is going to be:

[tex](4.6)(10^{-3}) \ mols \ CO_2[/tex]

Knowing that Henry's law is given by:

[tex]C = KHP[/tex]

Where constants are given by:

C = Concentration  KH = Henry's law constant = [tex]0.033 m/atm[/tex]P = partial pressure = [tex]0.07 atm[/tex]

Before we can find the concentration of CO2 (and hence the moles of CO2), we first need to find its partial pressure.  We look up the vapor pressure of water at 25º and find it to be 0.03 atm.  Since the total pressure is equal to 0.1 atm, this mean the partial pressure of:

 

[tex]CO_2 = 0.1 \ atm - 0.03 \ atm = 0.07 \ atm[/tex]

Now using Henry's law, we find the concentration:

[tex]C = (0.033)*( 0.07) = (2.31)*(10^{-3})[/tex]

Converting to moles of CO2, we have:

[tex](2.31)*(10^{-3})*( 2) = (4.6)*(10^{-3})[/tex]

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In the reaction below the total mass of calcium in the reactants is 40. What is the total mass of calcium in the products?

Answers

Answer:

40

Explanation:

The total mass of calcium in the products is 40

What is the total mass number?

The mass number (represented by the letter A) is defined as the total number of protons and neutrons in an atom. Consider the table below, which shows data from the first six elements of the periodic table. Consider the element helium. Its atomic number is 2, so it has two protons in its nucleus.

How do you find the mass number?

Together, the number of protons and the number of neutrons determine an element's mass number: mass number = protons + neutrons. If you want to calculate how many neutrons an atom has, you can simply subtract the number of protons, or atomic number, from the mass number.

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list of charge of elements that do not form compound easily​

Answers

Answer:

The highlighted words in the explanation.

Explanation:

A clue comes by considering the noble gas elements, the rightmost column of the periodic table. These elements—helium, neon, argon, krypton, xenon, and radon—do not form compounds very easily, which suggests that they are especially stable as lone atoms. What else do the noble gas elements have in common?

1. Which of the following statements pertaining to the ionic solids represented below are true?
(0)
1.
Both structure are ductile.
II. Structure (1) has a higher melting point than structure (ii)
III. Both structures conduct electricity in the solid state.
IV. Both structures conduct electricity in the liquid state.

Answers

Answer:

B

Explanation:

so A is nosense C and D the question is saying the stament for a being repersentation of solid not whether eletric or not

what is the molecular formula for sodium sulphur and oxygen​

Answers

Answer: Na2SO4

The molecular formula for sodium sulphur and oxygen​ is: (Na2SO4)

,  Hope this helps :)

Have a great day!!

ΕΛΑ
1
a
C
Copper(II) nitrate decomposes on heating. The reaction is endothermic.
2Cu(NO),(s) → 2CuO(s) + 4NO2(g) + 0,(9)
Sketch a reaction pathway diagram for this reaction to include the
activation energy
[3]
b Draw an energy cycle to calculate the standard enthalpy change for
this reaction, using enthalpy changes of formation.
[3]
Calculate the enthalpy change for this reaction using the following
enthalpy changes of formation.
AH, [Cu(NO, ),(s)] = -302.9 kJ mol-'
AH, [CuO(s)] =-157.3 kJ mol-!
AH [NO,(g)] = +33.2 kJ mol-!
[3]
d Copper(II) sulfate is soluble in water. A student dissolved 25.0 g of
copper(II) sulfate in 100 cm of water in a polystyrene beaker stirring
all the time. The temperature of the water fell by 2.9 °C.
i Calculate the enthalpy change of solution of copper(II) sulfate.
(specific heat capacity of water = 4.18 Jg1 °C ; relative
molecular mass of copper(II) sulfate = 249.7 g mol-')
[3]
ii Suggest one source of error in this experiment and explain how
the error affects the results.
[2]
[Total: 14]

Answers

This problem provides information about the decomposition of copper(II) nitrate to copper(II) oxide and dinitrogen monoxide; for example, it is endothermic, the enthalpies of formation and the chemical reaction, as well as copper (II) sulfate which when dissolved in water, exhibits a temperature decrease:

[tex]2Cu(NO_3)_2(s) \rightarrow 2CuO(s) + 4NO_2(g) + O_2(g)[/tex]

First of all, we can draw the reaction pathway as shown on the attached figure, by taking into account the positive enthalpy change as it is endothermic, so that the products turn out with higher energy than the reactants, for it to be positive. In addition, keep in mind that top point is the activation energy the reaction needs to take place.

Next, we calculate the enthalpy change for this reaction by using the general formula which subtracts the enthalpy of formation of products and reactants with each species' correct stoichiometric coefficient:

[tex]\Delta H=2\Delta _fH_{CuO}+4\Delta _fH_{NO_2}+\Delta _fH_{O_2}-2\Delta _fH_{Cu(NO_3)_2}[/tex]

So we plug in the given enthalpies of formation:

[tex]\Delta H=2(-157.3)+4(33.2)+(0)-2(-302.9)=424.0 kJ/mol[/tex]

Finally, we go over the calorimetry experiment, whereby the total heat absorbed by the copper(II) sulfate is calculated via the general heat equation, which includes the heat loss from the solution of water and the salt:

[tex]Q_{rxn}=-mC_w\Delta T\\\\Q_{rxn}=-(100+25)g*4.18\frac{J}{g\°C}*-2.9\°C=1515.25J[/tex]

By dividing the previous answer by the moles of salt:

[tex]n=25.0g*\frac{1mol}{249.7g}=0.100mol[/tex]

We can obtain the enthalpy change of solution of the copper salt:

[tex]\Delta _{dissolution}H=\frac{1,515.25J}{0.100mol} \\\\\Delta _{dissolution}H=15,134J/mol=15.1kJ/mol[/tex]

To conclude, it is important to note that one possible source of error is we are assuming the solution has the same specific heat to that of water and that is not necessarily true. Also, we are neglecting any heat transfer to and from the surroundings despite the polystyrene beaker is considered a heat isolator, which means the results cannot necesarilly be accurate and the enthalpy change could have turned out higher or lower in a rigoruous experiment.

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Which pair of objects is experiencing the greatest gravitational force?
2 kg
2 kg
A.
d = 5 m
2 kg
2 kg
B.
dolm
5 kg
skg
doim
3 kg
skg
OD
da 5 m

Answers

Answer:

c

Explanation:

Helium (he) has two valence electrons, and these electrons are located in the 1s subshell. Without using the periodic table, in which group and period is helium located?.

Answers

helium is in group 8 and period 1

put these atoms in order of increasing radius: Na, Mg,Cl, P

Answers

Answer:

Cl < P < Mg < Na

Explanation:

Cl must have the smallest radius because it is located to the right of the remaining elements on the same row. P  must have the second smallest radius because it is located to the right of the remaining elements on the same  row. Mg must have the Third smallest radius because it is located to the right of Na on the same row.  Therefore, Na has the Largest radius.

I hope it helps.

Metallic bonding is...

a
a type of covalent bond.
b
a type of ionic bond.
c
an attraction between positive and negative ions.
d
an attraction between positive ions and electrons.

Answers

Answer:

d an attraction between positive ions and electrons

How many moles of methane are produced when 25. 1 moles of carbon dioxide gas react with excess hydrogen gas.

Answers

Answer:

25.1 moles

Hence it can be seen that when 25.1 moles of carbon dioxide gas react with excess hydrogen gas, 25.1 moles of methane gas are produced.

How many moles of atoms are in 3.00 g of 13^C?

Answers

Answer:

1) 1.39 * 10²³ atoms

Explanation:

At a pressure of 125 atm, a sample of a gas has a volume of 150 L. What pressure does it have when the gas is compressed to 40 L? show work

Answers

Answer:

???

Explanation:

I have no clue sorry

20
How do you solve this ?

Answers

Answer:

eight oxygen atoms

Explanation:

This formula shows that in one mole of this compound, there are 3 moles of Ca atoms that combine with 2 moles of the PO4(phosphate) groups, which gives a total of 2 moles of P atoms and 8 moles of 0 atoms.

PLEASE HELP WILL MARK BRAINLIEST

Answers

Answer:

the answer is 150 in centimeters

What is the correct term for plants releasing water from their leaves which then evaporates?

A.precipitation
B.transpiration
C.condensation

Answers

Answer:

Transpiration is the correct answer mark me brainliest

What are the major reservoirs for sulfur

Answers

Answer:

the ocean, the ocean floor basalts, evaporite deposits and reduced marine sediments.

Explanation:

tornadoes form when updrafts from thunderstorms begin to _____

First answer that is correct gets brainly

Answers

Tornadoes form when updrafts from thunderstorms begin to interact with strong wind shear and develop a rotating column of air.

Updrafts are powerful vertical currents of air that occur within thunderstorms, caused by the rapid heating of the Earth's surface and the subsequent convective process. These updrafts carry warm, moist air upward, creating a conducive environment for the formation of severe weather phenomena.

When the updrafts encounter wind shear, which is the change in wind speed and direction with height, it can lead to the development of horizontal vorticity. Wind shear creates a rotating motion within the storm, where air at different heights starts to rotate at different speeds, generating a horizontal spin.

As the updraft continues to intensify, it tilts the rotating column of air from horizontal to vertical, forming a mesocyclone. The mesocyclone is a critical component in tornado formation. It acts as a localized area of strong rotation within the storm, extending from the cloud base to the mid-levels of the atmosphere.

Under specific conditions, such as the presence of a strong updraft, a well-developed mesocyclone, and further enhancement from other atmospheric factors, the mesocyclone can contract and intensify into a tornado. The process is complex and influenced by various meteorological factors, but the interaction between updrafts, wind shear, and the development of rotation plays a fundamental role in tornado formation.

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what is the formula for cadmium (ii) chlorate?

Answers

Answer:

a chemical compound

Explanation:

copper(ii) chlorate is a chemical compound of the transition metal copper and the chlorate anion with basic formula cu(cio)3 and 2

what word describes when tiny droplets of one liquid are finely dispersed within another liquid?

Answers

When tiny droplets of one liquid are finely dispersed within another liquid it is called emulsion.

Emulsion can be defined as the process by which two liquids that are not miscible come together to form a mixture.

The emulsion mixture usually consists of an oil phase and a water phase.

The oil phase appears as droplets when dispersed (mixed with) the water phase.

The uses of emulsion include:

It is used in chemical industries for production.

It is used for production of medicine.

Digestion of fatty food components in the intestine takes place through the process of emulsion.

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5. When argon was discovered, it was placed between chlorine and potassium, even though the periodic
table at that time was organized by increasing atomic weight. Why did scientists choose to place argon
before potassium?

Answers

because the modern periodic table is according to icnreasing atomic numbers.Ar has the atomic number 18 and potassium 19 so Argron is placed before K in the Modern periodic table.

In a few minutes, you will work with your partner to create three dances—one for each of the three phases. Each dance will represent the molecular freedom of movement of that particular phase.

If needed, navigate back to My Work to refer to your homework from Lesson 1.4. Then, begin brainstorming ideas for movements that would show these phases.

Dance ideas for solids:


Dance ideas for liquids:

Dance ideas for gases:

Answers

Stay still and shake for solids cause they can’t move move a little bit in a circle for liquid and move around a lot and really fast for gas

Which sample is a pure substance?zinc oxidesugar dissolved in waterpond watersoil.

Answers

Answer:

Oxide sugar dissolved in water pond

because water + sugar= sugar melts but the oxide purifys the water.

Explanation:

#carryonlearning!

Can elements from group 1 and 2 show up as pure elements in nature? Except Hydrogen

Answers

Answer:

No. Although alkali metals and alkaline earth metals are found in nature, they  are not found as pure elements. Group 1 and 2 are found in their chemical compounds, not pure form.

The reactants A and B react completely in a sealed container to form a product. What is the mass of the product of the reaction between 3.0 grams of reactant A and 5.7 grams of reactant B?

Answers

Answer:

I'm pretty sure it is 8.7

Explanation:

and btw you are fineeee

An iron object alloyed with cobalt rusts more quickly than a pure iron object. However, an iron object alloyed with manganese rusts less quickly than a pure iron object under the same conditions. This is true because: __________

a. cobalt is a stronger reducing agent than iron
b. iron is a stronger reducing agent than manganese
c. cobalt exhibits more metallic character than either iron or manganese in the iron-manganese alloy

Answers

Rusting is an electrochemical reaction. Iron rusts faster when alloyed with cobalt than when alloyed with manganese because, in the iron-manganese alloy, manganese is rendered the anode and iron is rendered the cathode

An alloy is a combination of two metals. There are various reasons for producing alloys such as greater tensile strength, corrosion resistance and improved aesthetic appearance.

When iron is alloyed with cobalt, the iron rusts faster than pure iron because iron is rendered the anode and cobalt is rendered the cathode. When the iron is alloyed with manganese, it rusts more slowly than pure iron because in the iron-manganese alloy, manganese is rendered the anode and iron is rendered the cathode.

Missing parts;

An iron object alloyed with cobalt rusts more quickly than a pure iron object. However, an iron object alloyed with manganese rusts less quickly than a pure iron object under the same conditions. This is true because

(1) cobalt is a stronger reducing agent than iron

(2) iron is a stronger reducing agent than manganese

(3) cobalt exhibits more metallic character than either iron or manganese

(4) in the iron-manganese alloy, manganese is rendered the anode and iron is rendered the cathode

(5) in the iron-cobalt alloy, cobalt is rendered the anode and iron is rendered the cathode

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How many mL of 0.100 M NaCl would be required to make a 0.0365 M solution of NaCl when diluted to 150.0 mL with water?

Answers

Answer:

54.75 mL

Explanation:

First calculate the number of moles of NaCl in the 150mL solution of NaCl

0.0365 moles should be present on 1000cm3 or 1dm3 of water.

1L = 1 dm3

1 mL = 1 / 1000 dm3

150 mL = 150/1000 dm3 = 0.15 dm3

If x moles are present in 0.15 dm3,

x/ 0.15 = 0.0365

We get x= 0.0365 × 0.15 mol

Now x amount of moles should be taken from the initial 0.100 M NaCl solution

So 0.1 moldm-3 = 0.0365× 0.15 mol / V

we get V = 0.05475 dm3

V= 0.05475 L

V= 54.75 mL

Please help I have a C in advance chemistry

Answers

Answer:

I think it's 2.50M IM NOT SURE THOUGH SO I RECOMMEND WAITING FOR ANOTHER ANSWER

when calculating specific heat what if the change in temperature is negative?

Answers

Answer:

If AT and q are negative, then heat flows from an object into its surroundings. If a substance gains thermal energy, its temperature increases, its final temperature is higher than its initial temperature, then AT>0 and q is positive.

What is carbon? What does it do?

Answers

Answer:

Carbon is in carbon dioxide, which is a greenhouse gas that works to trap heat close to Earth. Carbon is the chemical backbone of life on Earth. Carbon compounds regulate the Earth's temperature, make up the food that sustains us, and provide energy that fuels our global economy. Most of Earth's carbon is stored in rocks and sediments. The rest is located in the ocean, atmosphere, and in living organisms

Explanation:

Hope it helps. Can you give me BRAINLIEST ANSWER. Thank you

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