If an atom has 7 protons, 8 neutrons and 9 electrons, what is the mass number?

Explanation:

covalent bonds

Two covalent bonds form between the two oxygen atoms because oxygen requires two shared electrons to fill its outermost shell.

Answer:

Mass = 96 g

Explanation:

Given data:

Mass of oxygen required = ?

mass of Al = 110 g

Solution:

Chemical equation:

4Al + 3O₂     →     2Al₂O₃

Number of moles of Al:

Number of moles = mass/molar mass

Number of moles = 110 g/ 27 g/mol

Number of moles = 4 mol

Now we will compare the moles of Al and oxygen.

                     Al           :           O₂

                      4            :          3

Mass of oxygen:

Mass = number of moles × molar mass

Mass = 3 mol ×  32 g/mol

Mass = 96 g

Answer: The correct answer is option A. [tex]Na^+\text{ and }Cl^-[/tex]

Explanation:

An ionic compound is defined as the compound formed by the complete transfer of electrons from one element (forming cation) to another element (forming anion)

Sodium (Na) is an element having atomic number 11 and its electronic configuration is [tex]1s^22s^22p^63s^1[/tex]

It will loose 1 electron to form [tex]Na^+[/tex] ion (cation)

Chlorine (Cl) is an element having atomic number 17 and its electronic configuration is [tex]1s^22s^22p^63s^23p^5[/tex]

It will gain 1 electron to form [tex]Cl^-[/tex] ion (anion)

The ionic compound so formed will have the chemical formula of NaCl.

Hence, the correct answer is option A. [tex]Na^+\text{ and }Cl^-[/tex]

Answer:

I think is answer B

but you can chek

Answer:

C

Explanation:

All salts are ionic compounds. Think about NaCl. Na+ is a cation and Cl- is an anion. NaCl form an ionic compound and are then considered a salt.

Answer:

1. Temp of gas 21C, 6.2

2.Temp of gas 294, Volume of gas 0.78cm3

Explanation:

Just answered on Edge

Answer:

picture

Explanation:

edge 2021

Answer:

magnesium nitride

Explanation:

Answer:

C) The nuclear waste leaked into groundwater, and exposed humans to radiation that could potentially cause cancer.

Explanation:

your welcome girlies <33

The nuclear waste leaking into groundwater and exposing humans to radiation was how nuclear plant impacted the human population.

This is referred to a thermal power station in which the heat source is a nuclear reactor with radioactive elements.

The waste leaked into groundwater, and exposed humans to radiation that could potentially cause cancer which was how it affected the surrounding human population and why option C was chosen.

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Answer:

d - Meteor: A streak of light made when an object burns up as it enters earth’s atmosphere

Explanation:

The best description of what Jackson saw is a meteor which is a streak of light made when an object burns up as it enters earth's atmosphere.

A meteor is made up of rocky and sometime iron mass. They are believed to have formed since the early formation of the earth.

Answer:

Mass of lime produced = 19.0 g

Explanation:

Given data:

Mass of lime produced = 11.2 g

Mass of limestone react = ?  

Solution:

Chemical equation:

CaCO₃     →      CaO + CO₂

Balanced chemical equation:

CaCO₃     →      CaO + CO₂

Number of moles of lime:

Number of moles = mass / molar mass

Molar mass of lime 56.1 g/mol

Number of moles = 11.2 g/ 56.1 g/mol

Number of moles = 0.19 mol

Now we will compare the moles of CaO and CaCO₃  from balance chemical equation.

                    CaO        :           CaCO₃

                      1             :             1

                     0.19          :          0.19

Mass of limestone react:

Mass = number of moles × molar mass

Mass = 0.19 mol × 100.1 g/mol

Mass = 19.0 g

Answer:

It's called a theory because it has not been proven yet. so we can not claim it to be a fact without proof.

Answer: There is no concrete evidence.

Explanation: If we could do an experiment and create the Big Bang and watch it happen and study it, it would be law. It's for the same reason that evolution is considered a theory. We are not watching it take place and there is no eye witness account of evolution happening because evolution happens over millions and millions of years. If we could sit here and watch the universe be created without need for simulations or theories, then it would be law.

Explanation:

Rubidium is in Group 1 and exists as Rb+ ions.

Sulfur is in Group 16 and exists as S2- ions.

To form a compound containing rubidium and sulfur, the charges of the ions must be equal.

Therefore there are 2 rubidium and 1 sulfur atoms.

=> Chemical formula is Rb2S.

Sodium is also in Group 1 and exists as Na+ ions.

Oxygen is also in Group 16 and exists as O2- ions.

Therefore there are 2 sodium and 1 oxygen atoms.

=> Chemical formula is Na2O.

The chemical formula of the compounds form are as follows;

Discussion:

To form a compound between rubidium and sulfur, the net charge must be zero

As a result, we need 2 rubidium and 1 sulfur atoms.

Similarly, Sodium, Na is in Group 1 and ionises as Na+ ions.

Oxygen, O is in Group 16 and ionises as O2- ions.

To form a compound between Sodium and Oxygen, the net charge must be zero

As a result, we need 2 Sodium and 1 Oxygen atoms.

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Salt added : 14.5 g

Given

17% salt solution

71 ml water

Required

salt needed

Solution

%mass = (mass solute : mass solution) x 100%

71 ml water = 71 g water(density = 1 g/ml)

mass solute = x

[tex]\tt 17\%=\dfrac{x}{x+71}\times 100\%\\\\0.17(x+71)=x\\\\0.17x+12.07=x\\\\0.83x=12.07\\\\x=14.5[/tex]

Answer:

Dynamic equilibrium only occurs in reversible reactions, and it's when the rate of the forward reaction is equal to the rate of the reverse reaction. These equations are dynamic because the forward and reverse reactions are still occurring, but the two rates are equal and unchanging, so they're also at equilibrium.

Answer:

By IdowShadow the cool man

Explanation:

Dynamic equilibrium only occurs in reversible reactions, and it's when the rate of the forward reaction is equal to the rate of the reverse reaction. These equations are dynamic because the forward and reverse reactions are still occurring, but the two rates are equal and unchanging, so they're also at equilibrium

Answer:

Molecules are made of two or more atoms

Molecules are made of atoms of the same element or different elements.

Molecules range in size.

Explanation:

A molecule is formed whenever two or more atoms combine. Hence we can define a molecule as a combination of two or more elements that are combined chemically and can not be separated by any physical means.

Molecules may be composed of the same atoms as in O2, F2 etc or different atoms as in CO2, H2O, etc.

The sizes of molecules differ. Some molecules are quite small in size while others are quite large in size.

Answer:

Molecules are made of two or more atoms

Molecules range in size

Molecules are made of atoms of the same element or different elements.

Answer:

Ionization energy

Electron affinity

Electronegativity

Explanation:

Answer:

Chlorine

Explanation:

Answer:

Chlorine

Explanation:

The first Ionization energy for sodium is one and one-half times larger than the electron affinity for Chlorine. Thus, it takes more energy to remove an electron from a neutral sodium atom than is given off when the electron is picked up by a neutral chlorins atom.

1. 18 L

2. 20.832 L

Given

Combustion of ethane

Required

Volume of CO₂

Solution

Avogadro's Law :

In the same T,P and V, the gas contains the same number of molecules  

So the ratio of gas volume will be equal to the ratio of gas moles  

V₁/n₁=V₂/n₂

1. From equation, mol ratio of C₂H₆ : CO₂ ⇒ 2 : 6

so the volume of CO₂ :

= 6/2 x 6 L

= 18 L

2. mol ethane (MW=32 g/mol) :

= mass : MW

= 10 g : 32 g/mol

= 0.31

mol CO₂ :

= 6/2 x 0.31

= 0.93

The volume CO₂(assume at STP) = 20.832 L

Answer:

Solid

Explanation:

because their molecules are tightly packed.

According to the forces of attraction, at  room temperature, the greatest attractive forces exist between particles of a solid.

Forces of attraction  is a force by which atoms in a molecule  combine. it is basically an attractive force in nature.  It can act between an ion  and an atom as well.It varies for different  states  of matter that is solids, liquids and gases.

The forces of attraction are maximum in solids as  the molecules present in solid are tightly held while it is minimum in gases  as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.

The physical properties such as melting point, boiling point, density  are all dependent on forces of attraction which exists in the substances.

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Answer:

km

Explanation:

Answer:

miles yryryeyeueheueueueueueyeyeyeyey

Answer:

486 grams

Explanation:

No of moles = mass in gram / molar mass

Mass in gram = No of moles × molar mass

Molar mass of CaCO3 = 40+12+(16*3)

= 40+12+48 = 100 amu

Mass in gram = 4.86 × 100

Mass in gram 486 grams

Answer:

b

Explanation:

Explanation:

a) K(s) + I2(s)  --> KI(s)

The balanced equation is;

2K(s) + I2(s)  --> 2KI(s)

b) Mg(s)  +  Br2(l)  --> MgBr2(s)

The balanced equation is;

Mg(s)  +  Br2(l)  --> MgBr2(s)

c) KBr(aq)  +  AgNO3(aq)  --> KNO3(aq)  + AgBr(s)

The balanced equation is;

KBr(aq)  +  AgNO3(aq)  --> KNO3(aq)  + AgBr(s)

d) KClO3(s)  --> KCl(s)  +  O2(g)

The balanced equation is;

2KClO3(s)  --> 2KCl(s)  +  3O2(g)

e) C2H6(g)  +  O2(g)  -->  CO2(g)  + H2O(l)

The balanced equation is;

2C2H6(g)  +  7O2(g)  --> 4CO2(g)  + 6H2O(l)

f) Al(s)  +  O2(g)  --> Al2O3(s)

The balanced equation is;

4Al(s)  +  3O2(g)  --> 2Al2O3(s)

g) P4(s)  +  H2(g)  --> PH3(g)

The balanced equation is;

P4(s)  +  6H2(g)  --> 4PH3(g)

Answer: 55.233 moles of oxygen will react with 500 g of hexane.

Explanation:

To calculate the number of moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]

Given mass of hexane = 500g

Molar mass of hexane = 86 g/mol

Putting values in above equation, we get:

[tex]\text{Moles of hexane}=\frac{500g}{86g/mol}\\\\\text{Moles of hexane}=5.814mol[/tex]

The chemical equation for the reaction of burning of hexane in air follows:

[tex]2C_6H_{14}+19O_2\rightarrow 12CO_2+14H_2O[/tex]

By stoichiometry of the reaction:

2 moles of hexane reacts with 19 moles of oxygen

So, 5.814 moles of hexane will react with = [tex]\frac{19}{2}\times 5.814=55.233moles[/tex] of oxygen

Hence, 55.233 moles of oxygen will react with 500 g of hexane.

Answer:

:)

Explanation:

Water (chemical formula: H2O) is a transparent fluid which forms the world's streams, lakes, oceans and rain, and is the major constituent of the fluids of organisms. As a chemical compound, a water molecule contains one oxygen and two hydrogen atoms that are connected by covalent bonds.

Answer:

H2O

Explanation:

Thats the formula :P

Answer:

0.9m/s

hope it helps....

Answer:

ΔT = 0.78 °C

Explanation:

Given data:

Mass of Al = 9.5 g

Specific heat capacity of Al = 0.9 J/g.°C

Temperature change = ?

Heat added = 67 J

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

67 J = 9.5 g × 0.9 j/g.°C × ΔT

67 J = 85.5 j/°C × ΔT

ΔT = 67 J  /  85.5 j/°C

ΔT = 0.78 °C