17 POINTS!!! JUST DO A B C D PLS!!!! PLS DONT COMMENT IF YOU DONT KNOW IT ITS DUE BY TOMORROW AND I CANT KEEP WASTING POINTS PLS

Answer:

If you are referring to the Precambrian time, the answer is 500 Million Years Ago.

Explanation:

Precambrian time is the time period that started with the formation of Earth and ended about 500 million years ago.

Answer:

it drifts through the atmosphere and the vapor absorbs heat then the warm air rises up therefore leaving the planet's surface and releasing the heat back into the upper part of the atmosphere

Answer

V= 19.68cm^3

Explanation:

V=a^3

a=2.70cm

V=2.70cm^3

2.70^3= 19.68

V=19.68cm^3

Answer:

V= 19.68 cm^3

Explanation:

V= a^3

V= 2.70cm^3

V= 19.68cm^3

Among electromagnetic waves, UV rays are most dangerous because exposure to these radiation cause serious problems in living organism. The energy of wave is 2.08×10⁻¹⁵J.

Electromagnetic wave is a wave which contain two component one is electric component and other is magnetic component. The electric and magnetic component are perpendicular to each other. There are so many wave that comes under electromagnetic wave like infrared wave , radio wave .There is a relation between energy of wave. frequency of wave

Mathematically,

E=hv

where,

E = energy of electromagnetic wave

h is planks constant having value 6.67×10⁻³⁴js

v= frequency of wave

substituting the given values

E= 6.67×10⁻³⁴js×3.12 x 10¹⁸ s⁻¹

E= 2.08×10⁻¹⁵J

Therefore the energy of wave is 2.08×10⁻¹⁵J.

To know more about electromagnetic wave, here:

https://brainly.com/question/12289372

#SPJ2

Answer:

1s2, 2s2, 2p6, 3s2, 3p2

Explanation:

see the guide on the given electron configuration examples

Answer:

An ionic bond occurs between two opposite charges are attracted

Explanation: Two opposite charges are attracted to each other

Answer:

Explanation:

Gymnastics

Answer: Gymnastics

The physical change is a modification in the structure of the chemical substance. Teeth tearing off a bite of a taco represents a physical change. Thus, option B is correct.

A physical change is an alteration in the structure of the chemical involved in the substance. In a physical change, the composition of the chemical remains intact and does not change. It includes changes in texture, temperature, shape, and phase of matter.

The processes like dissolving, boiling, cutting, melting, bending, and freezing are said to be physical changes. The teeth-bitting tacos result in smaller bites is a physical change as there is a change in the shape and size but not the composition.

Therefore, option B. the teeth tearing tacos is an example of physical change.

Learn more about physical change here:

https://brainly.com/question/18690541

#SPJ6

[tex]\mathfrak{\huge{\pink{\underline{\underline{AnSwEr:-}}}}}[/tex]

Actually Welcome to the Concept of the Chemical Bonding.

Since we know that, calcium shares 2 electrons and Bromide being a halogen accepts 1 electron at a time,

So 2 bromides combine together to form a bond with Calcium, so we get as,

Ca2+ + 2Br -----------------------> CaBr2

CaBr2 is the compound formed.

Answer:

48 cups

Explanation:

16 x 3.5 = 48

Since one gallon is 16 cups, it would be done like this

Answer:

A prefix

Explanation:

you're welcome

The covalent molecules named as,

So, option B is correct one.

To learn more about covalent molecules,

https://brainly.com/question/1646189

#SPJ2

Answer:

73 days

Explanation:

From the question given above, the following data were obtained:

Half life (t½) = 18.2 day.

Original amount (N₀) = 0.70 g

Amount remaining (N) = 0.04375 g

Time (t) =.?

Next, we shall determine the rate of decay of the isotope. This can be obtained as follow:

Half life (t½) = 18.2 day.

Decay constant (K) =.?

K = 0.693 / t½

K = 0.693 / 18.2

K = 0.038 /day

Finally, we shall determine the time taken for the isotope to decay to 0.04375 g. This can be obtained as follow:

Original amount (N₀) = 0.70 g

Amount remaining (N) = 0.04375 g

Decay constant (K) = 0.038 /day

Time (t) =.?

Log(N₀/N) = kt /2.303

Log (0.70/0.04375) = (0.038 × t) /2.303

Log 16 = (0.038 × t) /2.303

1.2041 = (0.038 × t) /2.303

Cross multiply

1.2041 × 2.303 = 0.038 × t

Divide both side 0.038

t = (1.2041 × 2.303) / 0.038

t = 72.97 ≈ 73 days

Therefore, it will take approximately 73 days for the isotope to decay to 0.04375 g

Answer:

molecular number

Explanation:

because it shows exact numbers

Answer:

See explanation

Explanation:

When the bromine free radical attacks 2,3-dimethylbutane, two free radicals may result. One of them is primary (formed by attack on then end -CH3 group) the other is secondary.

Recall that the order of stability of free radicals is tertiary > secondary > primary > methyl.

Hence the secondary free radical is more thermodynamically stable hence it is the major free radical formed in the first propagation step.

50.5 km to ft is 165682.4

Answer:

the other guy is right its 165682.415

Answer:

1. Richter 2. Moment

Hope this helps !!

The correct answer is B: 121 and 123 Atomic Mass.

Mass spectrometers only detect stable isotopes.

Almost all elements exhibit isotopy. Isotopy is a phenomenon whereby atoms of the same atomic number have different atomic masses. The relative atomic mass of each element is the weighted average of the masses of all its isotopes.

Owing to the phenomenon of isotopy, the relative atomic mass of elements are not whole numbers.

The isotopes recorded by a mass spectrometer are stable isotopes of an element. The two stable isotopes of antimony are  Sb-121 and Sb-123. These two appear in its mass spectrum.

https://brainly.com/question/23431172

We have that

the Carbon isotopes represents a pair of isotopes

Option B

From the question we are told

Which of the following represents a pair of isotopes?

Generally

Isotopes

This is defined as variant forms of an element with variant atomic mass but same proton number

Therefore

the Carbon isotopes represents a pair of isotopes

For more information on this visit

https://brainly.com/question/17756498

Answer:

no

Explanation:

Answer:

nnmnm

Explanation:

Answer:

atomic number 8 and atomic number 12

Explanation:

atomic number 8 and atomic number 12 , element with the atomic number 8 is oxygen, and the element with atomic number 12 is Magnesium

Magnesium has low ionization energy, hence higher tendency to loose its two outermost electrons to form positive ion.

Oxygen has high electron affinity, hence higher tendency to accept or gain electrons to form negative ion.

The electronegativity difference between the element with atomic number 8 and element with atomic number 12 is greater for the formation of ionic bond

There are two types of chemical compound one is covalent compound and other is ionic compound, covalent compound formed by sharing of electron and ionic compound formed by complete transfer of electron. Therefore, the correct option is option C.

Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.

An ionic compound is a metal and nonmetal combined compound.  Ionic compound are very hard. They have high melting and boiling point because of strong ion bond.

atomic number 8 =oxygen

atomic number 12= Magnesium

Magnesium has a low ionization energy and so a greater proclivity to lose its two outermost electrons to create a positive ion. Because oxygen has a high electron affinity, it is more likely to accept or acquire electrons to create a negative ion.

Therefore, the correct option is option C.

To learn more about chemical compound, here:

brainly.com/question/26487468

#SPJ2

Answer:

D: 4, 5

Explanation:

Answer:

motion

Explanation:

i just know things