Answer:
B. Lindsay measures the sizes of the craters on the Moon.
Explanation:
Science is about making a hypothesis, doing experiments, making observations, recording data, analyzing data, interpretation of the data, and writing meaningful conclusion. Here Lindsay measures the sizes of the craters on the Moon, which falls under making observations and recording data so Lindsay is ding experiments.
Dominick is simply using technology, Murray is simply guessing a number and Isabel’s invention falls under engineering.
6. This part of Earth's atmosphere blocks the sun's harmful rays. (4 points)
Answer:
Ozone layer AKA ozone shield
Explanation:
I did this test too! :)
Based on the reactivities of the elements involved, which reaction will form products that are more stable than the reactants?
A.
2AlBr3 + 3Zn → 3ZnBr2 + 2Al
B.
CaBr2 + 2Na → 2NaBr + Ca
C.
MgBr2 + H2 → 2HBr + Mg
D.
BaBr2 + Ca → CaBr2 + Ba
E.
2LiBr + Ba → BaBr2 + 2LiBased on the reactivities of the elements involved, which reaction will form products that are more stable than the reactants?
A.
2AlBr3 + 3Zn → 3ZnBr2 + 2Al
B.
CaBr2 + 2Na → 2NaBr + Ca
C.
MgBr2 + H2 → 2HBr + Mg
D.
BaBr2 + Ca → CaBr2 + Ba
E.
2LiBr + Ba → BaBr2 + 2Li
Answer: The correct option is B.
Explanation: All the given reactions are a type of single displacement reactions.
Single displacement reactions are defined as the reactions in which a more reactive metal displaces a less reactive metal in a chemical reaction.
General equation for these reactions is:
[tex]AB+C\rightarrow CB+A[/tex]
For the given reactions, we will use the reactivity series. The metal which lies above in the reactivity series will easily displace the metal which lies below in the reactivity series.
Option A: For this reaction, zinc lies below aluminium in the reactivity series. Hence, zinc will not be able to displace aluminium in the chemical reaction.
Option B: For this reaction, Sodium is more reactive than calcium as it lies above in the reactivity series. Hence, sodium will easily displace calcium in the given chemical reaction.
Reaction follows:
[tex]CaBr_2+2Na\rightarrow 2NaBr+Ca[/tex]
Option C: For this reaction, hydrogen lies below magnesium in the reactivity series. Hence, hydrogen will not be able to displace magnesium in the chemical reaction.
Option D: For this reaction, Calcium lies below barium in the reactivity series. Hence, calcium will not be able to displace barium in the chemical reaction.
Option E: For this reaction, barium lies below lithium in the reactivity series. Hence, barium will not be able to displace lithium in the chemical reaction.
Reactivity series is attached below.
Answer : The reaction form products that are more stable than the reactants will be:
(B) [tex]CaBr_2+2Na\rightarrow 2NaBr+Ca[/tex]
Explanation :
Single displacement reactions : It is defined as the reactions in which a more reactive metal displaces a less reactive metal in a chemical reaction.
The general equation is:
[tex]AB+C\rightarrow CB+A[/tex]
According to the reactivity series, the metal which lies above in the reactivity series will easily displace the metal which lies below in the reactivity series.
(A) [tex]2AlBr_3+3Zn\rightarrow 3ZnBr_2+2Al[/tex]
In this reaction, zinc is less reactive than aluminum as it lies below in the reactivity series. Hence, zinc will not be able to displace aluminium in the chemical reaction. This reaction will not takes place.
(B) [tex]CaBr_2+2Na\rightarrow 2NaBr+Ca[/tex]
In this reaction, sodium is more reactive than calcium as it lies above in the reactivity series. Hence, sodium will easily displace calcium in the given chemical reaction.
(C) [tex]MgBr_2+H_2\rightarrow 2HBr+Mg[/tex]
In this reaction, hydrogen is less reactive than magnesium as it lies below in the reactivity series. Hence, hydrogen will not be able to displace magnesium in the chemical reaction. This reaction will not takes place.
(D) [tex]BaBr_2+Ca\rightarrow CaBr_2+Ba[/tex]
In this reaction, calcium is less reactive than barium as it lies below in the reactivity series. Hence, calcium will not be able to displace barium in the chemical reaction. This reaction will not takes place.
(E) [tex]2LiBr+Ba\rightarrow BaBr_2+2Li[/tex]
In this reaction, barium is less reactive than lithium as it lies below in the reactivity series. Hence, barium will not be able to displace lithium in the chemical reaction. This reaction will not takes place.
What best describes the advantage of using the model of a food web?
Investigates a problem in a zoological park
Helps visualize feeding relationships in nature
Predicts which predator will eat which prey
Always provides 100% accuracy
Answer: Helps visualize feeding relationships in nature
Explanation:
A food web in nature is a interconnection of food chains. In the food chains the food is distributed among various organisms, when organism is consumed by the another.
A scientific model is a kind of simulation that can be used to mimic the natural processes occurring in nature. These can be useful in learning, understanding and demonstrating the natural process.
Among the options given, Helps visualize feeding relationships in nature is the correct option. This will help in determining how food chains are related in a food web depending upon the feeding relationship between the organisms.
When a cold beverage is placed outside, the gas particles cling to the side of the can and become water droplets. This is due to which change of state?
Condensation
Evaporation
Melting
Freezing
The answer is condensation.
Have a great day :)
When bonding occurs, _______ is formed.
A. a new substance with new properties
B. the same substance
C. a different substance with exactly the same properties
I think A is the correct answer but i am not positive
What is the purpose of drawing a Bohr model of an atom
A salt crystal has a mass of 0.15 mg. How many NaCl formula units does it contain?
0.15mg = 0.00015g
Na =22g/mol
Cl= 35g/mol
35g/mol + 22g/mol = 57g/mol
0.00015g * 1 mol/ 57 g =2.63 * 10⁻⁶
0.00015g * 1 mol/ 57 g * NA/1mol = 2.63 * 10⁻⁶ NA
2.63 * 10⁻⁶ * 6.02 * 10²³ = 15.8326 * 10¹⁷
Answer:
2.56×10^-6 moles
Explanation:
Number of formula units is the same as the number if moles of NaCl present.
Number of moles= mass/ molar mass
Molar mass of NaCl= (23+35.5)= 58.5gmol-1
Given mass of NaCl= 0.15×10^-3g
Number of moles= 0.15×10^-3/58.5
Number of moles = 2.56×10^-6 moles
Which of the following is true for all chemical reactions? The total mass of the reactants increases. The total mass of the reactants equals the total mass of the products. The total mass of the products is greater than the total mass of the reactants. The total mass of the products is less than the total mass of the reactants.
The total mass of the reactants equals the total mass of the products, because matter is not created or destroyed in the reaction.
A sealed bottle is full of air. The volume of the bottle is decreased, but the temperature remains constant. What other change occurs in the bottle?
A.
The air pressure will increase.
B.
The air pressure will decrease.
C.
The number of air molecules will increase.
D.
The number of air molecules will decrease.
The other change that will occur in the bottle is that A. The air pressure will increase.
Why?If volume changes in a closed container, while temeprature remains constant, the phenomenon is described by Boyle's Law:
[tex]P1*V1=P2*V2[/tex]
Let's give some arbitrary values to these variables:
P1= 1 atm
V1= 2 L
P2= ?
V2= 1 L
Calculating the final pressure (P2):
[tex]P2=\frac{P1*V1}{V2}=\frac{1 atm*2 L}{1 L}=2 atm[/tex]
So, the final pressure is higher than the initial pressure (P2>P1). That means that Pressure and Volume are inversely proportional.
Have a nice day!
Water (3030 g ) is heated until it just begins to boil. If the water absorbs 5.49×105 J of heat in the process, what was the initial temperature of the water?
The initial temperature of the water was 56.7 °C.
Step 1. Calculate the temperature change.
The formula for the heat (q) absorbed is
q = mCΔT
We can solve this equation to get
ΔT = q/(mC)
q = 5.49 × 10⁵ J; m = 3030 g; C = 4.184 J·°C⁻¹g⁻¹
∴ ΔT = 5.49 × 10⁵ J/(3030 g × 4.184 J·°C⁻¹g⁻¹) = 43.30 °C
Step 2. Calculate the initial temperature
ΔT = T_f – T_i = 100°C – T_i = 43.30 °C
T_i = 100 °C – 43.30 °C = 56.7 °C
What is the chemical formula for the compound magnesium perchlorate? Use the list of polyatomic ions and the periodic table to help you answer.
The chemical formula for the compound magnesium perchlorate is Mg(ClO₄)₂
Magnesium perchlorate or Mg(ClO₄)₂ is an ionic compound.
Perchlorate here is an anion which is represented by ClO₄⁻. Perchlorate is a polyatiomic anion, where one Cl atom is bonded to four O atoms.
The magnesium cation is represented by Mg²⁺
So one Mg²⁺ cation combines with two ClO₄⁻ anion to form one molecule of Mg(ClO₄)₂
Answer: Mg(ClO₄)₂
Explanation: Correct on PLATO.
A sample of gas has a mass of 827 mg . Its volume is 0.270 L at a temperature of 88 ∘ C and a pressure of 975 mmHg . Find its molar mass
Steps:
Mw = w * R * T / p * V
T = 88 + 273 => 361 K
p = 975 mmHg in atm :
1 atm = 760 mmHg
975 mmg / 760 mmHg => 1.28 atm
Therefore:
= 0.827 * 0.0821 * 361 / 1.28 * 0.270
= 24.51 / 0.3456
molar mass = 70.92 g/mol
in chlorine gas, two chlorine atoms join to form a Cl2 (chlorine 2) molecule. How many pairs of valence electrons do the atoms share? What type of covalent bond is formed?
In chlorine gas, two pairs of valence electrons the atoms share and a non- polar covalent bond is formed.
What is covalent bond?Covalent bond is defined as a type of bond which is formed by the mutual sharing of electrons to form electron pairs between the two atoms.These electron pairs are called as bonding pairs or shared pair of electrons.
Due to the sharing of valence electrons , the atoms are able to achieve a stable electronic configuration . Covalent bonding involves many types of interactions like σ bonding,π bonding ,metal-to-metal bonding ,etc.
Sigma bonds are the strongest covalent bonds while the pi bonds are weaker covalent bonds .Covalent bonds are affected by electronegativities of the atoms present in the molecules.Compounds having covalent bonds have lower melting points as compared to those with ionic bonds.
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A layer of sediment goes through a series of steps on its way to becoming sedimentary rock. These steps are summarized below. Read the steps carefully, and then place them in the correct order. The sediment is gradually buried and compacted. The sediment is deposited by wind, flowing water, or other natural processes. Dissolved minerals completely cement the sediment together.
Answer:
1. The sediment is deposited by wind, flowing water, or other natural processes.
2. The sediment is gradually buried and compacted.
3. Dissolved minerals completely cement the sediment together.
Explanation:
Weathering is the breakdown of rock by agents such as wind and water. Erosion is the transporting of the broken rock material, or sediments, to a new location, where it is deposited.
As more sediment is deposited, it stacks up in layers. Eventually, the upper layers put pressure on the lower layers. This causes sediments to pack closer together in a process called compaction.
Through the process of cementation, minerals from groundwater form between sediment grains, connecting the grains together to form rock.
The rocks formed from deposition, compaction, and cementation of sediment are sedimentary rocks.
The sediment goes through a series of steps to become sedimentary rock, which includes deposition, burial and compaction, and cementation.
Explanation:The correct order of the steps in which a layer of sediment becomes sedimentary rock is as follows:
The sediment is deposited by wind, flowing water, or other natural processes. The sediment is gradually buried and compacted. Dissolved minerals completely cement the sediment together.
what is density? what does it tell you about substance?
Hello!
Explanation:
↓↓↓↓↓↓↓
Density is the amount of mass in a given volume. It's a derived unit of measure. It is equal to mass divided by volume. It's measured in units such as grams per cubic centimeter and grams per milliliter. Density is the ratio of mass to volume. Density is a physical property of an object. It is degree of compactness of a substances. Relative density is used to separate solids, liquids, and gases. The gas in the container rises to the top because it has the least density. The liquids separate into individual layers based on their relative densities. The least dense liquid is on top. The most dense liquid is on bottom. The solids sink to the bottom of the container because they have the greatest density.
Hope this helps!
Thank you for posting your question at here on Brainly.
-Charlie
Answer:
The density of a substance is the relationship between the mass of the substance and how much space it takes up (volume). The mass of atoms, their size, and how they are arranged determine the density of a substance. Density equals the mass of the substance divided by its volume; D = m/v.
Explanation:
how many electrons does a Mn atom have in its 3d subshell
One Mn atom contains 5 electrons in it's 3d subshell.
Mn atom has [tex]$\boxed5$[/tex] electrons in its 3d subshell.
Further explanation:
The electronic configuration is the distribution of electrons of an atom in the atomic orbitals. There are two states for an electron: ground as well as the excited state. The configuration of the atom in the lowest possible energy levels is called the ground-state electronic configuration. When an electron jumps from the stable ground state to some higher level, that state is called the excited state and the electronic configuration corresponding to this state is known as the excited-state half-filled configuration.
The filling of electrons in different energy levels or orbitals is done in accordance with the following three rules.
1. Aufbau principle: The principle states that the electrons are filled in various orbitals in the increasing order of their energies as follows:
1s<2s<2p<3s<3p<4s<3d<4p<5s<4d<5p<6s<4f<5d<6p<7s<5f<6d<7p
2. Hund’s rule: Electron pairing will not start until each orbital is singly occupied.
3. Pauli’s exclusion principle: According to this principle, all the four quantum numbers [tex]$$\left({n,\;l,\;{m_l},\;{m_s}}\right)$$[/tex] for any two electrons can never be the same. In an orbital, the spin of two electrons has to be different. If one electron has the clockwise spin, the other would have the anticlockwise spin and vice-versa.
Manganese is a transition metal of the first transition series. The atomic number of Mn is 25. Its electronic configuration is [tex]$$\left[{{\text{Ar}}}\right]\;3{d^5}4{s^2}$$[/tex] . It has half-filled d-subshell. (Refer to the attached image). So the total number of electrons in 3d subshell of Mn is 5.
Learn more:
1. Determine the ion with configuration [tex]$$\left[{{\text{Ar}}}\right]\;3{d^2}$$[/tex] : https://brainly.com/question/7599542
2. Identification of element which has electron configuration [tex]$$1{s^2}2{s^2}2{p^2}3{s^1}$$[/tex] : https://brainly.com/question/9616334
Answer details:
Grade: High School
Subject: Chemistry
Chapter: Electronic configuration of the elements
Keywords: Mn, electrons, 3d subshell, 5 electrons, transition metal, 25, transition series, half-filled, aufau principle, Pauli’s exclusion principle, Hund’s rule.
the three main ideas behind capitalism definded by Adam's smith are
The three main ideas behind capitalism as defined by Adam Smith are "competition, self interest, and laissez-faire," since Smith was a heavy proponent of the "invisible hand of the market".
If light has a frequency of 2.4 x 10 to the 14th Hz what is it’s wavelength?
The equation we need to use to solve this is: c=λν
c is the speed of light (2.998 x 10^8 m/s)
λ is the wavelength, which we're gonna solve for
ν is the frequency ( 2.4 x 10^14 Hz )
First, plug in the values we were given into the equation
2.998 x 10^8 m/s= (λ)(2.4 x 10^14 Hz)
Next, divide both sides of the equation by 2.4 x 10^14 Hz to solve for the wavelength (λ)
λ= 1.249166667 x 10^-6 m
Round to 2 significant figures
λ= 1.2 x 10^-6 m
A student makes several observations about a piece of iron. Which observation describes a chemical property of the iron?
A.
Its mass is 52 grams.
B.
Its density is 7.9 grams/centimeter3.
C.
It rusts when exposed to air.
D.
It conducts electricity.
Answer:The correct answer is option C.
Explanation:
Chemical property of the substance is a property which is observed in a chemical reaction during which identity or composition of the substance changes.
Iron when exposed to air ,react with atmospheric oxygen to from ferric oxide which is a reddish brown in color.Also termed as Rust.
[tex]Fe(s)+O_2(g)\righhtarrow Fe_2O_3(s)(\text{Reddish brown})[/tex]
Hence, the correct answer is option C.
Answer:
The correct answer is option C.
Explanation:
Chemical property is defined as the property of a substance which is observed during a reaction where the chemical composition identity of the substance gets changed.
For Example: reactivity , toxicity etc.
Physical property is defined as the property which can be measured and whose value describes the state of physical system. For Example: State, density etc.
The chemical property observed by the the student is that iron rusts when exposed to air. The oxygen present in the air reacts with iron to form reddish brown compound named rust.
[tex]4Fe(s)+3O_2(g)\rightarrow 2Fe_2O_3(s)[/tex]
Here, iron's reactivity is observed which is a chemical property of the iron.
Where mass , density and being a electricity conductor are physical properties.
Write the formula of the compound in the grid when a precipitate forms and a (—) when no precipitate form?
Answer :
(D) [tex](NH_{4})_{2}S[/tex] (C) [tex]Ba(NO_{3})_{2}[/tex] (B) [tex]CuCl_{2}[/tex]
(A) [tex]K_{2}SO_{4}[/tex] _ [tex]BaSO_{4}[/tex] _
(B) [tex]CuCl_{2}[/tex] [tex]Cu_{2}S_{2}[/tex] _
(C) [tex]Ba(NO_{3})_{2}[/tex] BaS
Explanation :
(1) Reaction for A + B
[tex]K_{2}SO_{4}[/tex] + [tex]CuCl_{2}\rightarrow[/tex] 2KCl + [tex]CuSO_{4}[/tex]
In this reaction, there is no precipitate formed as the products are souble.
(2) Reaction for A + C
[tex]K_{2}SO_{4}[/tex] + [tex]Ba(NO_{3})_{2}\rightarrow[/tex] [tex]BaSO_{4}[/tex] + [tex]KNO_{3}[/tex]
In this reaction, [tex]BaSO_{4}[/tex] is formed as precipitate as it do not dissolve.
(3) Reaction for A + D
[tex]K_{2}SO_{4}[/tex] + [tex](NH_{4})_{2}S\rightarrow[/tex] [tex]K_{2}S[/tex] + [tex](NH_{4})_{2}SO_{4}[/tex]
In this reaction, there is no precipitate formed as the products are souble.
(4) Reaction for B + D
[tex]2CuCl_{2}[/tex] + [tex]2(NH_{4})_{2}S\rightarrow[/tex] [tex]4NH_{4}Cl+Cu_{2}S_{2}[/tex]
In this reaction, [tex]Cu_{2}S_{2}[/tex] is formed as precipitate as it do not dissolve.
(5) Reaction for B + C
[tex]CuCl_{2}[/tex] + [tex]Ba(NO_{3})_{2}\rightarrow[/tex] [tex]BaCl_{2}[/tex] + [tex]Cu(NO_{3})_{2}[/tex]
In this reaction, there is no precipitate formed as the products are souble.
(6) Reaction for C + D
[tex]Ba(NO_{3})_{2}[/tex] + [tex](NH_{4})_{2}S\rightarrow[/tex] BaS + [tex]2NH_{4}NO_{3}[/tex]
In this reaction, BaS is formed as precipitate as it do not dissolve.
Which method is more convenient for you to use ?
Is their any specific options..?
Your question is subjective and depends on the context, individual preferences, and the methods available. The choice of method often depends on efficiency, ease of use, and the information at hand.
Explanation:The question you asked, 'Which method is more convenient for you to use?' is subjective and depends on the individual's preferences, the situation, and the options available. As a tutor, it's difficult to provide a specific answer without knowing the context or the methods being referred to. But in general, the choice of method often depends on factors such as efficiency, ease of use, and the information you have at hand. It's essential to evaluate all of these factors before making a decision on the most convenient method to use.
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Why does acetone have more surface tension than methanol?
Atoms are electrically because they have the same number of protons and electrons. A. charged B. neutral
assuming that seawater is a 3.50 mass % aqueous solution of NaCl, what is the molality of seawater?
Hey there!
Consider 100 g of solution:
Mass of NaCl = 3.50% of mass of seawater
( 3.50 / 100 ) * 100 => 3.50 g
Number of moles as shown below:
Molar mass NaCl = 58.44 g/mol
n = Mass / molar mass
n = 3.50 / 58.44 => 0.059 moles of NaCl
Mass of sweater:
Mass of solution - Mass of NaCl
100 - 3.50 = 96.5 g
96.5 g in Kg :
96.5 / 1000 => 0.0965 Kg
Therefore ,calculate molality by using the following formula:
molality = number of moles of solute / mass of solution
molality = 0.059 / 0.0965
molality = 0.61 m
Hope That helps!
What is the electron configuration of an element with atomic number 20? A. 1s2 2s2 2p6 3s2 3p5 B. 1s2 2s2 2p6 3s2 3p6 C. 1s2 2s2 2p6 3s2 D. 1s2 2s2 2p6 3s2 3p6 4s2 E. 1s2 2s2 2p6
D. The number of electrons equals the atomic number for a neutral element. Each number after the letter refers to the number of electrons in that shell. So for D, 2+2+6+2+6+2 = 20 electrons, which is equal to the atomic number.
D. 1s2 2s2 2p6 3s2 3p6 4s2
Hope this helps!
What is the first basic metal on the periodic table
The first basic metal on the periodic table is lithium.
Explanation:The first basic metal on the periodic table is lithium. It is part of Group 1, which is known as the alkali metals. Alkali metals are very reactive and form basic (alkaline) solutions when they react with water.
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The first basic metal on the periodic table is lithium, part of the alkali metals in group 1 of the periodic table. These metals are known for their reactivity, forming ions to create ionic compounds which are usually soluble in water.
Explanation:The first basic metal on the periodic table is lithium. It's part of the alkali metals which constitute group 1 of the periodic table. The other alkali metals are sodium, potassium, rubidium, cesium, and francium. Despite hydrogen also being in group 1, it is not considered a metal but a nonmetal.
These alkali metals are known for their high reactivity. They readily form ions with a charge of 1+ to create ionic compounds, which usually dissolve in water. In addition, they react vigorously with water to produce hydrogen gas and a basic solution of the metal hydroxide, hence justifying the name alkali metal.
Many of these elements may not occur naturally in an uncombined state because they can readily react with water and oxygen in the air. Yet, when isolated from their naturally occurring minerals, they react very slowly with air due to the formation of a protective nonreactive film coating also known as passivation.
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If the amount of atoms of each type on the left and right sides of a reaction differs, What must be done to balance it
1.Should be left alone
2.Coefficients are placed in front of the reactants and/or products
3.subscripts are placed in the chemical formulas
4.Superscripts are placed in the chemical formulas
Try the third option
HELP EASY QUESTION JUST NEED TO BE SURE PLEASE REASSURE ME IT IS RIGHT!! :)
Which of these is likely to happen in the absence of the stratosphere?
We may have to bear the impact of a meteorite.
We may not experience storms, winds, and clouds.
Mixing of air due to convection currents may stop.
Increased exposure to radiation may cause skin ailments.
pretty sure its d since its one less layer of our atmosphere but I haven't learned this yet I'm just using common sense
Answer:
Increased exposure to radiation may cause skin ailments.
Hope this helps (;
Imagine that you were in charge of creating a red and purple fireworks display. Name two combinations of compounds you could use .
Answer: For red color firework we will use combination of strontium carbonate with lithium carbonate and for purple color we will use combination of strontium salts with copper salts.
Explanation:
There are various metallic salts which on performing flame test imparts characteristic color to the flame and this color is due to presence metal ions.
Color seen during the fireworks are mainly due to the presence of the metal ions present in the material from which the firework is made.
for example : strontium carbonate on flame test imparts bright red color to the flame where as barium chloride imparts green color to the flame.
The combinations of compounds are:
For red color firework we will use the combination of strontium carbonate with lithium carbonate because combination strontium and lithium ions both imparts red color to the flame.
For purple color we will use the combination of strontium salts with copper salts because combination of strontium and copper ions imparts purple color to the flame.
Arctic animals often expand their hunting territory during the winter when the ice cap expands to cover more of the ocean surface. What property of water contributes most to their ability to do so?*
Explanation: During winters, there is decrease in temperature which leads to the freezing of water molecules.
The state change occurs from liquid state to solid state.
In case of water, the inter-molecular forces between the molecules decreases which leads to the increase in volume.
Which in turn leads to the decrease in the density of solid (ice). This increase in density tends to the floating of ice on water.
[tex]Density=\frac{Mass}{Volume}[/tex]
Thus, on freezing, the water expands and hence, there will be more space for the arctic animals to hunt in winters.