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zimovet [89]
3 years ago
9

The mean radius of the Earth is 6,371 km, and 70.8% of its surface is covered by water. What is the surface area of the Earth co

vered by land?
Chemistry
1 answer:
Marina CMI [18]3 years ago
8 0

Answer:

147,558,601 sqkm

Explanation:

The earth is spherical in shape;

area of sphere = 4πr²

if 70.8% is covered by water then 100-70.8 will be land,

= 29.2%

area occupied by land = (29.2/100) * 4πr²

                                = 0.292*4*3.142*(6371)²

                        =147,558,601 sqkm

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How many moles of TNT would be detonated if you used 539.88 grams of TNT? The structure of TNT is C7H5N3O6. Round your answer to
Kruka [31]

Answer:

Moles of TNT = 2.38 moles

Explanation:

First , calculate the molar mass of the compound TNT

The formula is : C7H5N3O6

How to calculate molar mass?

Molar mass : It is the mass of substance in grams which is present in 1 mole of the compound.It is calculated by:

Molar mass = Number of atoms x the atomic mass of the element

Atomic mass of the elements are given below :

C = 12.0107

H = 1.0079

N = 14.0067

O = 15.9994

Molar mass of C7H5N3O6 =

= (7 x C) + (5 x H) + (3 x N) + (6 x O)

= 7(12.0107) +5(1.0079) + 3(14.0067) + 6(15.9994)

Molar mass = 227 .13 gram/mole

Mole are calculated using the formula:

Moles =\frac{given\ mass}{Molar\ mass}

Given mass = 539.88 grams

Molar mass = 227.13 g/mole

Moles =\frac{539.88}{227.13}

= 2.3769

Moles = 2.38 moles

5 0
3 years ago
QUICK PLEASE
Trava [24]

Answer: 2.52 M

Explanation:

The product of molarity (moles/litre) and volume in litres yields moles, and the numbers of moles in two solutions means dilute and concentrated are equal, which is expressed by the following equation: 

M_1V_1=M_2V_2

$$Given that\\M $1=12.0 \mathrm{M}$ or mole $/ \mathrm{L}$\\$\mathrm{V} 1=420 \mathrm{ml}$\\$\mathrm{M} 2=$ ?\\$\mathrm{V} 2=2.0 \mathrm{~L}$ or $2000 \mathrm{ml}$\\\\$\mathrm{M} 1 \mathrm{~V} 1=\mathrm{M} 2 \mathrm{~V} 2$\\$\mathrm{M} 2=\mathrm{M} 1 \mathrm{~V} 1 / \mathrm{V} 2$\\$=12.0 * 420 / 2000$\\$=2.52 \ \mathrm{M}$

3 0
2 years ago
Click on the event or events that led to the formulation of the cell theory
Alexandra [31]
So back in 1665 Robert hook was able to view cells and describe them along with pictures, the reason he was able to see cells was because the microscope was invented a bit before, which allowed him to think about things differently, he was looking at a cork and saw squared objects, these objects were cells, according to him.

So while the cork was the reason he discovers cells on it in the first place,
The microscope was what allowed him to do that

So it’s (HOOKE LOOKING AT A CORK)
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8 0
3 years ago
When will diffusion slow down
scZoUnD [109]

Answer:

Exchange across cell membranes - diffusion. The higher the concentration gradient, the faster the rate of facilitated diffusion, up to a point. As equilibrium is reached the concentration gradient is much lower because the difference in concentrations is very small so the rate of facilitated diffusion will slow down and level off.

Explanation:

6 0
3 years ago
An atom of oxygen has atomic of 8 and a mass number of 18. How many of each type of subatomic particle doe it contain?
Tju [1.3M]
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Electrons = 8

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Neutrons = 10.
7 0
3 years ago
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