What is the charge of an Pb atom with 81 electrons?

Answer:

first theres the poliution  one of the biggest things thats starts global warming then theres recycle and non recycle because people mix there trash up when their not suppossed to.

Explanation:

The mass of unreacted zinc = 13 g

The reaction equation is the chemical formula of reactants and products

A reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reactants and products

Reaction

[tex]\tt Zn+2HCl\Rightarrow ZnCl_2+H_2[/tex]

mol ratio Zn : HCl = 1 : 2

[tex]\tt mol=V\times M\\\\mol=0.1~L(100~cm^3)\times 2~mol/L\\\\mol=0.2[/tex]

[tex]\tt \dfrac{1}{2}\times 0.2=0.1~mol[/tex]

[tex]\tt 0.1\times 65=6.5~g[/tex]

[tex]\tt 19.5-6.5=\boxed{\bold{13~g}}[/tex]

Answer: martin luther king jr

Explanation: He led peaceful protests against the discrimination that the people of the United State did against African American men, women, and children. He was a celebrity due to his have "I a dream speech" that he said in front of the lincoln memorial.  Plus he didn't approve of violence when trying to protest African American rights.

Answer:

Who is Martin Luther King and why is he famous?

Exsplanation

A Baptist pastor and civil rights activist, King worked to end legal segregation of blacks in the United States. He gave his famous “I Have a Dream” speech at the August 1963 March on Washington, and won the Nobel Peace Prize in 1964 at age 35 – the youngest man to have received the award.Apr 4, 2018

Answer:

is force acting in one direction

Answer:

hope this helps!

as described by the third of Newton's law of motion of classical mechanics, offices occurs in pairs such that is one object exerts a force on another object, then the second object exerts an equal and opposite reaction Force on the first.

Answer: If you think about it, B. would be the most reasonable answer with the given factors.

Answer:

3.41 x 10^7

Explanation:

Answer:

GAS .assumes the shape and volume of its container

particles can move past one another    

.compressible

lots of free space between particles

.flows easily

particles can move past one another

LIQUID assumes the shape of the part of the container which it occupies

particles can move/slide past one another

.not easily compressible

little free space between particles

.flows easily

particles can move/slide past one another

SOLID .retains a fixed volume and shape

rigid - particles locked into place

.not easily compressible

little free space between particles

.does not flow easily

rigid - particles cannot move/slide past one another

Answer:

hope it helps..

Explanation:

Number of protons

More information: The atomic number is used to identify an element, and the atomic number is the number of protons in the nuclei of an element. Every element has its own unique number of protons, and therefore, atomic number.

Answer:

before it evaporated into the air, it was on the Earth...and it could have been contaminated/dirtied. There isn't a process during evaporation that cleans water...you have to purify it yourself.

Explanation:

Answer:

Yes it is

Explanation:

calcium chloride  releases heat in an exothermic reaction.

yes.

hope is helps! :)

Answer:

9.32×10⁻³

Explanation:

Scientific notation is the way to express the large value in short form.

The number in scientific notation have two parts.

. The digits (decimal point will place after first digit)

× 10 ( the power which put the decimal point where it should be)

How to add the number in scientific notation with same exponent.

7.21 ×10⁻³ + 2.11 ×10⁻³

exponent of both values are same thus we will take it common.

[7.21 + 2.11 ]×10⁻³

9.32×10⁻³

Answer:

what is the question

Explanation:

what do you need help with

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\ [/tex]

From the question we have

[tex]density = \frac{85}{110} \\ = 0.772727272...[/tex]

We have the final answer as

The substance will float on water since it's density is less than that of water which is

1 g/cm³.

Hope this helps you

[tex]1 \: mol MgSO4 \: has \: 4 \: oxygens[/tex]

Thus ;

[tex]2 \: mols \: of \: should \: have \: 8 \: oxygens[/tex]

So the correct answer is (( 8 مول ))

The work by Mark : 100 J

Work is the transfer of energy caused by the force acting on a moving object  

Work is the product of force with the displacement of objects.  

Can be formulated  

[tex]\tt W=F\times d[/tex]

W = Work, J, Nm  

F = Force, N  

d = distance, m  

Mark is using 5N to push the box 20 m,

F = 5 N

d = 20 m

[tex]\tt W=5\times 20\\\\W=100~J[/tex]

Answer:

Vertebrate Endocrine Glands and Hormones

Unlike plant hormones, animal hormones are often (though not always) produced in specialized hormone-synthesizing glands (shown below). The hormones are then secreted from the glands into the blood stream, where they are transported throughout the body.

Answer:

Explanation:

Latent heat of fusion of zinc = 7.322 kJ / mol

molecular weight of zinc = 65 g

450 gram = 450 / 65 = 6.92 mole

Heat required to melt 450 g of zinc = 6.92 x 7.322 kJ

= 50.67 kJ .

= 50.7 kJ .

Answer:

group 5, period 7

Answer:

A solution is a homogeneous mixture consisting of a solute dissolved into a solvent . ... The solute is the substance that is being dissolved, while the solvent is the dissolving medium. Solutions can be formed with many different types and forms of solutes and solvents.

Answer:

A solution is a homogeneous mixture consisting of a solute dissolved into a solvent .

Explanation:

Answer:

He

O

Ge

Sr

Ba

Explanation:

An atom gets larger as the number of electronic shells increase; therefore the radius of atoms increases as you go down a certain group in the periodic table of elements.

In general, the size of an atom will decrease as you move from left to the right of a certain period.

Number of atoms : 2.245 x 10²⁴

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  

Can be formulated :

N = n x No

N = number of particles

n = mol

No = 6.02.10²³ = Avogadro's number

n= 3.73 moles

Number of atoms :

[tex]\tt 3.73\times 6.02\times 10^{23}=\boxed{\bold{2.245\times 10^{24}}}[/tex]

Answer:

[tex]it \: is : \\nuleic\: force\: of\: ( attraction \: and \: repulsion).[/tex]

Explanation:

[tex]this \: is \: because, \: for \: any \: type \: of \: chemical \\\: combination \: (bonding) \: to \: be \: possible, \\ there \: must \: exist\: an \: equilibrium \: between \: \\ the \: force \: of \: attraction \: and \: repulsion.[/tex]

Answer:

bonds are formed by joining atoms whether same or different elements to form molecules by uses of forces of attractions

Answer:

1.5 x 10⁵

Explanation:

Scientific notation always starts in the 1's place (1.)

Answer:

He should use black a light purple brown, tan, blue, and just a tiny bit of pink!

Hope this helps!!

Explanation:

If Johnny wanted to show the brightness of the stars, he should use blue, light blue, yellow, orange, red, and white.

The Milky Way is a huge collection of stars, dust and gas .

Hence , Johnny should use blue, light blue, yellow, orange, red, and white.

Learn more about milky way below

https://brainly.com/question/13956361

#SPJ2

The combination of beads should the student use for  the model :2 green, 3 blue and 12 yellow

In the chemical formula of a compound there are numbers:

1. The number indicates the number of atoms written after the element symbol

2. The number after the parentheses represents the number multiplied by the number of atoms in parentheses.

3. The number before the chemical formula shows the number of molecules behind it, which is usually used in equations

To calculate the beads needed to make a model, we must count the number of atoms of the Al₂(SO₄)₃ molecule

In the Al₂ (SO₄) ₃ molecule there are 3 atoms : Al, S, and O

So the combination of beads

2 green(for Al), 3 blue(for S) and 12 yellow(for O)

Answer:

2 blue, 3 yellow, and 12 green

Explanation:

Answer:

make a new friend if you lose one, Its part of life losing people thats what make us people grow and be more mature.

Answer:

graduated cylinder and a scale can be used to measure the volume of a substance. hope this is helpful

Explanation:

Answer:

hi..

Explanation:

The lower mantle is hotter and denser than the upper mantle and transition zone. The lower mantle is much less ductile than the upper mantle and transition zone. Although heat usually correspond s to softening rocks, intense pressure keeps the lower mantle solid. Geologists do not agree about the structure of the lower mantle.

hope this helps ._.

very hot at temperatures, i think i would set it to 43 degrees celsius as its much colder and better

hope this helps!