Answer:
coal is made from compressed plant matter and how exactly did plants grow on the surface of an ocean. (as there is no land mass beneath the arctic.)
Explanation:
it would be like finding a fly in an ice cube to simplify it.
They were surprised to find coal in arctic because ordinarily coal was supposed to be found in warm or hot environments and not cold region like the arctic.
The arctic is located at the far northern part of the world which is characterized by its extreme cold weather.
A limited vegetation of plants such as grasses, mosses and lichens are found in this region irrespective of the extreme cold weather through out the year.
Coal is a type of fuel gotten from fossils and deposits of plant vegetation.
Scientist has discovered that continents do move over time through a process called continental drift. This is the reason why limited vegetaion is found in the arctic leading to the formation of coal.
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Brandon is trying to remember how the physical and chemical properties of metals, nonmetals, and metalloids compare. He wrote some notes down, then looked in his textbook to see which notes were correct.
Which of Brandon's notes, listed below, are correct?
I. Metals are the best at conducting heat, and nonmetals are the worst.
II. Metals are the worst at conducting electricity, and nonmetals are the best.
III. The shape of nonmetals is easy to change, but the shape of metals or metalloids is difficult to change.
IV. Nonmetals are dull in appearance while metals are usually shiny.
V. Metals tend to have a high density, and nonmetals tend to have a low density.
Answer:
The correct ones are:
|
|||
|V
V
Explanation:
Answer:
1 for and 5
Ex
Study island
Where do diamonds come from?
Answer: Diamonds were first discovered and mined in India over 2,400 years ago.
Explanation: Over time, diamonds were found in many other areas around the world, including many in Africa. In today's trade, Africa, Russia, Australia, and Canada produce the most diamonds.
~Wonderopolis
Answer:
Diamonds are formed when under the heat and pressure of the earth's gravity. Diamonds have to be underground to be formed so they should be underground. Digging to Y11 is deep enough to find diamonds .
Inside the retina of our eyes are receptors called rods and cones. Rods measure the brightness we see and cones determine _____.
A) the color we see
B) the white we see
C) the dimness we see
D) the loudness we hear
Frosted glass and wax paper are ____.
A) transparent
B) translucent
C) clear
D) opaque
Answer:
B) translucent
Explanation:
Light only partially passes through them.
what two factors does elastic potential energy depend upon
Answer: Spring constant k as well as the distance stretched
Explanation:
Elastic potential energy is Potential energy stored as a result of deformation of an elastic object, such as the stretching of a spring. It is equal to the work done to stretch the spring, which depends upon the spring constant k as well as the distance stretched.
Why did the United States government set aside land for the first national parks?
A.
They wanted to settle the west as quickly as possible.
B.
They worried people would destroy the animals and land.
C.
They worried Native Americans wouldn’t have anywhere to go.
D.
They wanted to make sure all citizens would get a piece of land.
Answer:
b
Explanation:
hope it helps
Which of the following is a chemical reaction?
1- Dropping a sliced orange into a vat of Sodium Dydroxide
2-Cutting a piece of paper into two pieces
3-Filling a balloon with air
4-Freezing liquid Mercury
Answer:
1- Dropping a sliced orange into a vat of Sodium Dydroxide
Explanation:
The other answers (2-4) are only physical changes that don't change any chemical compositions.
Blast furnaces extra pure iron from the Iron(IIl)oxide in iron ore in a two step sequence. In the first step, carbon and oxygen react to form carbon monoxide:
2C(s)+O2(g) arrow 2CO(g)
In the second step, iron(lll) oxide and carbon monoxide react to form Iron and carbon dioxide:
Fe203(s) + 3CO(g) arrow 2Fe(s)+ 3CO2(g)
Suppose the yield of the first step is 71.% and the yield of the second step is 72.%. Calculate the mass of oxygen required to make 7.0 kg of iron.
Be sure your answer has a unit symbol, if needed, and is rounded to 2 significant digits.
Answer:
5.9 kg
Explanation:
We must work backwards from the second step to work out the mass of oxygen.
1. Second step
Mᵣ: 55.84
Fe₂O₃ + 3CO ⟶ 2Fe + 3CO₂
m/kg: 7.0
(a) Moles of Fe
[tex]\text{Moles of FeO} = \text{7000 g Fe} \times \dfrac{\text{1 mol Fe}}{\text{55.84 g Fe}} = \text{125 mol Fe}[/tex]
(b) Moles of CO
[tex]\text{Moles of CO} = \text{125 mol Fe} \times \dfrac{\text{3 mol CO}}{\text{2 mol Fe}} = \text{188 mol CO}[/tex]
However, this is the theoretical yield.
The actual yield is 72. %.
We need more CO and Fe₂O₃ to get the theoretical yield of Fe.
(c) Percent yield
[tex]\begin{array}{rcl}\text{Percent yield} &=& \dfrac{\text{ actual yield}}{\text{ theoretical yield}} \times 100 \, \%\\\\ 72. \, \% & = & \dfrac{\text{188 mol}}{\text{actual yield}} \times 100 \,\%\\\\0.72 &= &\dfrac{\text{188 mol}}{\text{actual yield}}\\\\\text{Actual yield} & = & \dfrac{\text{188 mol}}{0.72}\\& = & \textbf{261 mol}\\\\\end{array}[/tex]
We must use 261 mol of CO to get 7.0 kg of Fe.
2. First step
Mᵣ: 32.00
2C + O₂ ⟶ 2CO
n/mol: 261
(a) Moles of O₂
[tex]\text{Moles of O}_{2} = \text{261 mol CO} \times \dfrac{\text{1 mol O}_{2}}{\text{2 mol CO}} = \text{131 mol O}_{2}[/tex]
(b) Mass of O₂
[tex]\text{Mass of O}_{2}= \text{131 mol O }_{2} \times \dfrac{\text{32.00 g O}_{2}}{\text{1 mol O}_{2}} = \text{4180 g O}_{2}[/tex]
However, this is the theoretical yield.
The actual yield is 71. %.
We need more C and O₂ to get the theoretical yield of CO.
(c) Percent yield
[tex]\begin{array}{rcl}71. \, \% & = & \dfrac{\text{188 mol}}{\text{actual yield}} \times 100 \,\%\\\\0.71 &= &\dfrac{\text{4180 g}}{\text{actual yield}}\\\\\text{Actual yield} & = & \dfrac{\text{4180 g}}{0.71}\\\\& = & \text{5900 g}\\& = & \textbf{5.9 kg}\\\end{array}[/tex]
We need 5.9 kg of O₂ to produce 7.0 kg of Fe.
What improvements have been made in modern farming? Select all that apply.
1. machines can do more work over less time
2. better seeds sprout and grow much more quickly
3. trains can transport food over long distances faster
4. trains can transport the machines to rural farms once built
5. insecticides used to keep insects off the crops
Answer:
all of them except number 2
Explanation:
Answer:
1,3,4,5 the other perosn is correct
Explanation: That what my quiz said
Compare and contrast the dynamics of energy transfer between the Eocene Period and the Cryogenian Period. In which period would you say that Earth's system is experiencing a net gain in energy and in which period would you say that Earth's system is experiencing a net loss in energy
Answer:
The Eocene Period is experiencing net gain in energy while Cryogenian Period is experiencing a net loss in energy.
Explanation:
In Eocene Period, the population of mammals such as horses , whales and bats etc were high due to the presence of high amount of food and good atmospheric condition such as high temperature while the population of animals were low in Cryogenian Period due to the presence of very low temperature which experiencing loss of energy. Most of area of the earth consist of icy desert.
Which of the following is a chemical property of liquid water?
Its density is 1.00 g/cm3.
It reacts with sodium metal to form sodium hydroxide and hydrogen gas
It flows.
It freezes to form ice.
It boils at 100°C.
Answer:
B) it reacts with sodium metal to form sodium hydroxide and hydrogen gas
Explanation:
B is the only option that show a chemical property, density, freezing, and boiling points are physical properties.
a put question in screen shot
Answer:maybe 2
Explanation:
Answer:
2
Explanation:
1. What are the trends for atomic size across a period and down a group for the
main group elements?
2. Draw the following Lewis structures:
a) ammonium ion b) sulfur trioxide c) hydrogen cyanide
3. Using formal charge formula (or electronegativity differences), to determine
the following the best structure, OCS, COS or CSO.
Answer:
Here's what I get
Explanation:
1. Trends in atomic size
Atomic size tends to decrease from left to right across the Periodic Table.
You are adding one electron at a time. the electrons repel each other, so the size should increase.
You are also adding a proton to the nucleus. The additional attraction should pull the electrons closer to the nucleus.
The nuclear pull wins, so the atoms get smaller from left to right
Atomic size increases from top to bottom of a Group.
You are adding electrons to an extra shell, so the size should increase.
You are also adding protons to the nucleus, so the size should decrease.
The size of the outer shell wins, so the atomic size increases going down a Group.
2. Lewis structures
(a) Ammonium ion
N is the central atom. The N atom has the positive charge.
(b) Sulfur trioxide
S is the central atom, with a double bond to each of the three O atoms.
(c) Hydrogen cyanide
C is the central atom, with a triple bond to the N atom.
3. COS
The best structure is that of O=C=S. It has no formal charges.
The Lewis structures for the other arrangements have formal charges.
The correct answers of this question is given below.
1. The atomic size increases going down a Group.2. (a) Ammonium ion : The N atom has the positive charge. (b) Sulfur trioxide : Having double bond to each of the three O atoms. (c) hydrogen cyanide : Having a triple bond to the N atom.3. COS and it has no formal charges What is Periodic table?A table in which the chemical elements are arranged in order of increasing atomic number.A periodic table has 118 known elements The chemical elements are arranged from left to right and top to bottom in order of increasing atomic number.What is the explanation for this answers?1. Trends in atomic size : Atomic size tends to decrease from left to right across the Periodic Table.You are adding one electron at a time. the electrons repel each other, so the size should increase.You are also adding a proton to the nucleus. The additional attraction should pull the electrons closer to the nucleus.The nuclear pull wins, so the atoms get smaller from left to right.Atomic size increases from top to bottom of a Group.Adding electrons to an extra shell, so the size should increaseAdding protons to the nucleus, so the size should decrease.The size of the outer shell wins, so the atomic size increases going down a Group.2. Lewis structures :
(a) Ammonium ion : N is the central atom. The N atom has the positive charge. (b) Sulfur trioxides : S is the central atom, with a double bond to each of the three O atoms.(c) Hydrogen cyanide: C is the central atom, with a triple bond to the N atom3. COS
The best structure is that of O=C=S. It has no formal charges.The Lewis structures for the other arrangements have formal charges.Learn more about atomic size below,
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#SPJ2
How are electrons similar and different to the planet Earth?
Answer:
The planets themselves are composed of several trillions or quadrillions or more atoms. As far as hard science is concerned, it would be really hard to picture them as electrons. Conclusion: It can be said with a great accuracy that our planets are NOT huge electrons.
Rutherford's experiments showed that the mass of atoms was mostly concentrated in a very small region, with charge equal to the atomic number- the nucleus. He absolutely did not show, nor is it true, that electrons orbit the nucleus as if they were planets. That was a guess people made in trying to figure out how to picture the atom.
(Hope this helps) Sky
The process by which complex compounds are broken down by enzymes and by which many organic alcohols are formed is called
Answer:
fermentation
Explanation:
If is known how deep the water table in an area is, it is known how deep to dig to reach
Pores
The unsaturated zone
Solid rock
Groundwater
Answer:
grond water
Explanation:
What is the primary role of the United States Bureau of Counterterrorism?
о
to plan counterterrorist attacks
to create active counterterrorism groups
to encourage domestic counterterrorism activities
to advance counterterrorism efforts in other countries
o advance counterterrorism efforts in other countries
Answer:
D
Explanation:
E2020
I AM GIVING BRAINLIEST PLEASEE HELPPPP I NEED HELPPPPPP PLEAEEEEEE
63.2 g of BaCl 2 are dissolved in enough water to make a 634 mL solution. What is the molarity?
Answer:
0.479 M or mol/L
Explanation:
So Molarity is moles/litres of solution...often written as M=mol/L
So here we are given grams of BaCl2 which we have to convert to moles. To convert to moles of BaCl2 we have to divide 63.2 g BaCl2 by molar mass of BaCl2 which is 208.23 g/mol so you get 63.2/208.23 = 0.3035 moles of BaCl2
Second step is converting the 634mL to litres by simply dividing by 1000 because we know 1 litre has 1000ml so 634/1000 = 0.634L
Now we just plug these guys in our molarity formula M=mol/L
M= 0.3035/0.634 = 0.479 M or mol/L
Answer:
Interestingly enough, I'm not getting
0.0341% w/v
either. Here's why.
Start by calculating the percent composition of chlorine,
Cl
, in calcium chloride, This will help you calculate the mass of chloride anions,
Cl
−
, present in your sample.
To do that, use the molar mass of calcium chloride, the molar mass of elemental chlorine, and the fact that
1
mole of calcium chloride contains
2
moles of chlorine atoms.
2
×
35.453
g mol
−
1
110.98
g mol
−
1
⋅
100
%
=
63.89% Cl
This means that for every
100 g
of calcium chloride, you get
63.89 g
of chlorine.
As you know, the mass of an ion is approximately equal to the mass of the neutral atom, so you can say that for every
100 g
of calcium chloride, you get
63.89 g
of chloride anions,
Cl
−
.
This implies that your sample contains
0.543
g CaCl
2
⋅
63.89 g Cl
−
100
g CaCl
2
=
0.3469 g Cl
−
Now, in order to find the mass by volume percent concentration of chloride anions in the resulting solution, you must determine the mass of chloride anions present in
100 mL
of this solution.
Since you know that
500 mL
of solution contain
0.3469 g
of chloride anions, you can say that
100 mL
of solution will contain
100
mL solution
⋅
0.3469 g Cl
−
500
mL solution
=
0.06938 g Cl
−
Therefore, you can say that the mass by volume percent concentration of chloride anions will be
% m/v = 0.069% Cl
−
−−−−−−−−−−−−−−−−−−−
I'll leave the answer rounded to two sig figs, but keep in mind that you have one significant figure for the volume of the solution.
.
Explanation:
The mole concept will most likely be used in
calculating the average height of a mountain range.
measuring how many liters of gasoline are poured into a tank.
determining how many ozone molecules are lost in the atmosphere.
finding the mass of a piece of steak in a butcher shop.
Answer:
determining how many ozone molecules are lost in the atmosphere
Pls Mark as Brainliest!!! if this helps...
The mole concept The mole concept can be used to determine the number of ozone molecules are lost in the atmosphere.
The mole concept was introduced by Avogadro. The mole is the SI unit of amount of substance. According to Avogadro, one mole of a substance contains 6.02 × 10^23 atoms, ions, molecules etc.
The mole concept is important in many chemical calculations. The mole concept can be used to determine the number of ozone molecules are lost in the atmosphere. (option C)
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Which of the following presents a safety hazard while working in the science laboratory?
A knowing how to use equipment
B wearing safety goggles
C following directions
D working alone
Answer:
D working alone
Explanation:
Working alone is the only option that could potentially be a safety hazard; if you have no one watching your back, errors could occur, like dropping glass or burning your hand, and no one is around to help you.
Choices A, B, and C are not correct because those are all good safety standards.
How does the pressure of a container change as the volume is changed?
Answer: If the volume is decreased, the pressure would increase because the gas molecules have less space to move around. Same goes for the opposite; if the volume increased, the pressure would decrease because the molecules have more space to move and aren't packed as tightly .
Hope this helps!!!
Which statement best describes liquid water and water vapor at equilibrium?
A. Liquid water stops entering the gas phase.
O B. The concentration of liquid water equals the concentration of
water vapor.
C. The concentrations of liquid water and water vapor are stable.
D. The concentration of liquid water is zero.
C. The concentrations of liquid water and water vapor are stable. it describes the fact that liquid water and water vapor are at equilibrium.
EquilibriumAn equilibrium is achieved when no more water vapor can enter into the gas phase from the liquid water during evaporation process. This happens when a saturation is attained between liquid water and the vapor phase.Hence, option (c) is correct. The concentration of liquid water and water vapor will become stable.
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PLZ HELP OR WILL FAIL!!
Label A drop downs are: condensation, melting, sublimation
Label B drop downs are: condensation, melting, sublimation
Label C drop downs are: condensation, melting, sublimation
If a buffer has an initial pH of 6.34 and the acid has a Ka of 3.46 × 10-4, what is the ratio of conjugate base to weak acid in the buffer system?
Answer: The ratio of conjugate base to weak acid in the buffer system is 758 : 1
Explanation:
The dissociation constant for acid = [tex]K_a=3.46\times 10^{-4}[/tex]
pH = 6.34
First we have to calculate the value of [tex]pK_a[/tex].
The expression used for the calculation of [tex]pK_a[/tex] is,
[tex]pK_a=-\log (K_a)[/tex]
Now put the value of [tex]K_a[/tex] in this expression, we get:
[tex]pK_a=-\log (3.46\times 10^{-4})[/tex]
[tex]pK_a=3.46[/tex]
Now we have to calculate the ratio of conjugate base to weak acid in the buffer system
Using Henderson Hesselbach equation :
[tex]pH=pK_a+\log \frac{[\text {conjugate base}]}{[Acid]}[/tex]
Now put all the given values in this expression, we get:
[tex]6.34=3.46+\log \frac{[\text {conjugate base}]}{[Acid]}[/tex]
[tex]\frac{[\text {conjugate base}]}{[Acid]}=758[/tex]
Therefore, the ratio of conjugate base to weak acid in the buffer system is 758: 1
Answer:
A. 1:0.46
Explanation:
I took the test
What slows down heat energy from escaping the Earth?
Answer:
Greenhouse gases such as carbon dioxide and water vapor make an atmosphere around the earth and make less heat escape
Explanation:
How can the motion of atoms in the solid state of most substances be described?
Answer:
The molecules in a solid are stuck in a specific structure or arrangement of atoms. The atoms still vibrate and the electrons fly around in their orbitals, but the entire atom will not change its position.
Explain the different principles that allow roller coasters to rip and roar around the tracks. In your response, include how energy is transferred back and forth between kinetic and potential.
Answer:
In the roller coasters the potential energy that is given is the gravitational potential energy, which this energy increases its value as the object moves away from the earth, that is to say, the more height the roller coaster acquires the more gravitational potential energy it will have, and Said train where people usually get on the roller coaster will descend or descend with greater acceleration.
This gravitational potential energy once the mountain begins to descend or descend is converted into kinetic energy
Explanation:
This that we wrote above is considering that the roller coaster does not have curved routes but rectilinear, in the case that it had curved routes, a force would be added in addition to those written that is the centripetal force, it is the same force that appears in the centrifuges or dryers of clothes or the same washing machine. This force, the centripetal force is the force that draws a moving object, in a curvilinear path, towards the center of the curvature.
What does X represent for this transmutation?
96242Cm + X→ 98245Cf + 01n
gamma
+10e
24He
−10e
Answer:
24He
Explanation:
When a nuclide is bombarded with alpha particles, we notice an increase in its mass and charge since an alpha particle has a mass of four and a charge of +2. recall that nuclear equations must be balanced. That is, the masses and charges on the left hand six and the right hand side of the nuclear reaction equation must be exactly the same.
Looking at the nuclear reaction at hand, the total mass on the left hand side has to be 246 while the total charge on the left hand side of the equation will be 98. Coming over to the right hand side, the total masses are also found to be the same as a neutron with no charge and a mass of 1 is produced. Hence the nuclear reaction equation is balanced when an alpha particle (helium nucleus) is substituted for X in the equation.
Answer:
24HE
I took the test!
what is an example of a strong base?
HCl
NaCl
NaOH
HF
Answer:
The answer is NaOH
Explanation:
Strong bases are characterized by the fact that they dissociate completely in an aqueous solution. In this case, sodium hydroxide, NaOH, is classified as a strong base because it dissociates completely in an aqueous solution to form sodium cations, Na+, and hydroxide anions, OH−. Also, it is strong because it totally breaks in its ion. And the base which breaks totally in its atom called the strong base and which doesn't it that is a weak base.
Answer:
NaOH
Explanation:
Got it right in the test. Please mark as brainliest
0.450 moles of K2SO4 are dissolved in 195.0 mL of water. Calculate the molarity of the solution.
Answer:
2.31M
Explanation:
The following data were obtained from the question:
Mole of K2SO4 = 0.450 mole
Volume of water = 195.0 mL = 195/1000 = 0.195L
Molarity =...?
Molarity is defined as the mole of solute per unit litre of the solution. This can be expressed as:
Molarity = mole /Volume
With the above formula we can calculate the molarity of the K2SO4 solution as follow:
Molarity = mole /Volume
Molarity = 0.450/0.195
Molarity = 2.31M
