Unit 2 Test
What makes up all of the populations in an area?
they
O Niche
Habitat
Ecosystem
Community

Answers

Answer 1
the answer is community

Related Questions

What mass of potassium chloride, KCl, is produced when 12.6 g of oxygen, 02, is produced?

Answers

Mass of KCl= 19.57 g

Further explanation

Given

12.6 g of Oxygen

Required

mass of KCl

Solution

Reaction

2KClO3 ⇒ 2KCl + 3O2

mol O2 :

= mass : MW

= 12.6 : 32 g/mol

= 0.39375

From the equation, mol KCl :

= 2/3 x mol O2

= 2/3 x 0.39375

=0.2625

Mass KCl :

= mol x MW

= 0.2625 x 74,5513 g/mol

= 19.57 g

Which of the following is an example of a ball of clay undergoing a physical change?
I. The ball is thrown into the air
II. The ball is broken into two separate halves
lll. The ball is rolled along the ground
lV. The ball is flattened into a pancake like shape

Answers

I’m pretty sure it’s II, because from what I learned, physical change is stuff similar to II, chemical change is an object that has fully change its appearance, like Baking cake

Answer:

II. The ball is broken into two separate halve. The ball is still a ball. It is just in a different form.

IV. This one is also correct because it is only changing the physical state of the ball. The ball is still a ball.

At room temperature , 1 mL of water has a mass of 1 gram . What is the percent by mass of a 428 mL magnesium citrate ( solution containing 0.1 mol of magnesium citrate ?

Answers

Answer:

5.0% by mass

Explanation:

Percent by mass is 100 times the ratio between the mass of solute (Magnesium citrate) in the mass of solution.

Mass of Magnesium citrate -Molar mass: 214.41g/mol-:

0.1mol * (214.41g/mol) = 21.441g

Assuming the volume of the solution is just due the solvent -Water-, the mass of water is 428g.

Percent by mass is:

21.441g / 428g * 100 =

5.0% by mass

A chemist weighed out 2.9 g of nickel. Calculate the number of moles of nickel she weighed out. Be sure your answer has the correct number of significant digits.

Answers

Answer:moles = 2.9 g Ni × 1 mol Ni 58.69 g Ni = 0.0663 mol Ni

What is the molecular formula of paradichlorobenzene that has a molar mass of 147.g/mol and an empirical formula of C3CIH2?

Answers

Answer:

the molecular formula of paradichlorobenzene is C6H4CL2

y = (x-16)2 A. Shift the graph of y = x2 down 16 units. B. Shift the graph of y= x2 right 16 units. C. Shift the graph of y = x2 left 16 units. D. Shift the graph of y = x2 up 16 units.

Answers

Answer:

Uhmm i think i dont know the sent r 6un Dury r in eyeing in d7ue


Magnesium bromide is prepared in a laboratory using the reaction below. Typically, the magnesium bromide is recoveted as a solid by heating way the remaining water
Mg(s) + 2 HB-(aq) - MgBrac) + H200)
If 0.940 mole of HBr in solution is added to 16.5 grams of Mgo in a beaker and then is heated until dry, what are the expected contents of the beaker?

Answers

Can you give more examples?

Calculate the energy of a photon emitted when an electron in a hydrogen atom undergoes a transition from =3 to =1.

Answers

Answer:

[tex]1.936\times 10^{-18}\ \text{J}[/tex]

Explanation:

[tex]R_h[/tex] = Rydberg constant = [tex]2.178\times 10^{-18}\ \text{J}[/tex]

[tex]n_i[/tex] = Initial shell = 3

[tex]n_f[/tex] = Final shell = 1

We have the relation

[tex]\Delta E=R_h(\dfrac{1}{n_f^2}-\dfrac{1}{n_i^2})\\\Rightarrow \Delta E=2.178\times 10^{-18}(\dfrac{1}{1^2}-\dfrac{1}{3^2})\\\Rightarrow \Delta E=1.936\times 10^{-18}\ \text{J}[/tex]

The energy of the photon emitted here is [tex]1.936\times 10^{-18}\ \text{J}[/tex].

can someone help please?

Answers

What’s the question

Answer:

Genetic Factors: Bad tasting leaves, plant structure, types of stems, reproduction

Environmental: insects, pollution, terrain, soil conditions, pH of soil, fire, flood, heat wave, temperature, lack of air, drought,

Explanation:

Genetic factors are within the organism, the plant's own make-up. Environmental factors are conditions on the outside, in the soil, the atmosphere, and other organisms in the habitat.

Need help with question 3!
*please answer correctly*


A student increases the temperature of a 300cm3 balloon from 40°C to 110°C.

What will the new volume of the balloon be? Round your answer to one decimal point.

(To convert Celsius to kelvin, add 273.15)

Thank you!!!

Answers

Answer:

[tex]V_2=367.06\ cm^3[/tex]

Explanation:

Charles law states that volume of the gas is directly proportional to the temperature i.e.

[tex]\dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}[/tex]

We ave,

V₁ = 300 cm³

T₁ = 40°C = 40 + 273.15 = 313.15  K

T₂ = 110°C = 110 + 273.15 = 383.15 K

Let V₂ be the new volume.

[tex]V_2=\dfrac{V_1T_2}{T_1}\\\\V_2=\dfrac{300\times 383.15 }{313.15}\\\\V_2=367.06\ cm^3[/tex]

So, the new volume of the balloon is [tex]367.06\ cm^3[/tex].

element A it's valance number is 3 and element B it's valance number is 6 make it compound​

Answers

Answer:

A2B

Explanation:

A = 3

B = 6

exchange valencies

A6B3

A2B

If you have 90L of water, what is the volume?

Answers

Answer:

900

Explanation:

a roller coaster train with a mass of 500 kg stops at the top of a hill if the hill is 110 m high what is the potential energy of the train

Answers

Answer:

Answer is 5000

Explanation:

5000 is your answer

Answer:

what the other person says their wright

Explanation:

stay safe 2021

Stoichiometry :

2 AlCl3 + 3 MgSO4 --> Al2(SO4)3 + 3 MgCl2

If 633.1 g AlCl3 reacts, how many moles of MgCl2 are formed?

Answers

7.200318447 moles MgCl2

Which statement describes why the viscosity of water is lower than that of
olive oil?
A. The molecules that make up water have more kinetic energy than
the molecules that make up olive oil.
B. The molecules that make up water can more easily slide past one
another than the molecules that make up olive oil.
C. The molecules that make up water have less kinetic energy than
the molecules that make up olive oil.
D. The molecules that make up water are larger than the molecules

Answers

Answer:

Option B. The molecules that make up water can more easily slide past one another than the molecules that make up a olive oil.

The molecules that make up water can more easily slide past one another than the molecules that make up olive oil. Hence, option B is correct.

What is viscosity?

Viscosity is a term used to describe FLUIDS, which includes liquids and gases. Viscosity refers to the ability of a gas or liquid to resist flow.

Olive oil has a higher viscosity than water because it is a much larger molecule than water with larger dispersion forces.

Hence, option B is correct.

Learn more about viscosity here:

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How do you solve -8r=240

Answers

Answer:

You solve that dividing beach term by -8 and simplifying which for this answers will give you r=-30

Explanation:

Pls correct me if I’m wrong.

Hope this helps :)


A _____ is two or more substances that are together in the same place but are not chemically combined.

Answers

Answer:

Mixture

Explanation:

A mixture has two or more substances that are together in the same place but are not chemically combined .

HOPE THIS HELPS YOU;)

Use the periodic table to determine the molar mass of each of the following elements. Use the correct number of significant figures.

Potassium (K):
g/mol
Osmium (Os):
g/mol
Manganese (Mn):
g/mol

Answers

Answer:

Potassium (K):   39.10 g/mol

Osmium (Os):   190.23 g/mol

Manganese (Mn):   54.94 g/mol

Explanation:

Just got it right on Edge 2021

The molar mass of the following elements are

Potassium (K): 39.10 g/mol

Osmium (Os): 190.23 g/mol

Manganese (Mn): 54.94 g/mol

What is molar mass?

The molar mass of a substance is grams of one mole of that substance.

It can be calculated by dividing the atomic weight of the element, and the number of atoms found in that element.

Manganese is a transition metal with the atomic number 25.

Potassium is an essential mineral that is an alkali metal and its atomic number is 19.

Osmium is also a transition metal whose atomic number is 76.

Thus, the molar mass of the elements are, Potassium (K): 39.10 g/mol

Osmium (Os): 190.23 g/mol

Manganese (Mn): 54.94 g/mol

Learn more about molar mass

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Plant cells and animal cells were observed under a microscope. The characteristics of two cells are listed below.

Cell X: Has chloroplast
Cell Y: Does not have a cell wall

Which statement about the two cells is correct? (5 points)

a
Cell X has a cell membrane.

b
Cell X has a small vacuole.

c
Cell Y has a large vacuole.

d
Cell Y has chloroplast.

Answers

Answer:

The answer is B

Explanation:

ITs B

Answer:

Cell X has a cell membrane

Explanation:

I took the test and got it right.

PV=nRT is an example that deacribes the relationship between pressuee, volume,moles and temperature of a gas. This is an example of a

Answers

Answer:

This is an example of Avogadro equation

TRUE OR FALSE

If mechanical energy is conserved, the kinetic energy you end up with always equals the potential energy you lost.

Answers

........false.........

how many grams of ZrCl4 can be produced if 123 g of ZrSiO4 react with 85.0 g of Cl2?

Answers

Answer:

153.3 grams of ZrCl₄ are produced

Explanation:

The equation of the reaction is as follows:

ZrSiO₄ + Cl₂ ----> ZrCl₄ + SiO₂ + O₂

molar mass of ZrSiO₄ = (91 + 32 + 16 * 4) = 187.0 g/mol

molar mass of ZrCl₄ = (91 + 35.5 * 4) = 233.0 g/mol

molar mass of Cl₂ = (35.5 * 2) 71.0 g/mol

From the equation of reaction, 1 mole of ZrSiO₄ reacts with one mole of  Cl₂ to produce one mole of ZrCl₄

number of moles of ZrSiO₄ present in 123 g = 123/187 = 0.65 moles

number of moles of Cl₂ present in 85.0 g = 85.0/71.0 = 1.19 moles

therefore, ZrSiO₄ is the limiting reactant

123.0 g of ZrSiO₄ will react with excess Cl₂ to produce 123 * 233/187 grams of ZrCl₄ = 153.3 grams of ZrCl₄

Therefore, 153.3 grams of ZrCl₄ are produced

What is the amount of diamine silver that can be formed when 10.00 g AgCl is mixed with 1.00 L of 0.100 M NH3?

Answers

The amount of diamine silver chloride = 8.87 g

Further explanation

Given

10 g AgCl

1.00 L of 0.100 M NH3

Required

the amount of diamine silver

Reaction

AgCl + 2 NH₃ → [Ag(NH₃)₂]Cl

mol AgCl :

= mass : MW

= 10 g : 143,32 g/mol

= 0.0698

mol NH₃ :

= M x V

= 0.1 x 1

= 0.1

NH₃ as a limiting reactant

mol [Ag(NH₃)₂]Cl based on NH₃ :

= 1/2 x mol NH₃

= 1/2 x 0.1

= 0.05

Mass diamine silver :

= 0.05 x  177.3822 g/mol

= 8.87 g

2
A brick has a mass of 4.0 kg and the Earth has a mass of 6.0 x 10
Use this information to answer the questions below. Be sure your answers have the correct number of significant digits.
What is the mass of 1 mole of bricks?

?
How many moles of bricks have a mass equal to the mass
of the Earth?

Answers

Answer:mass of 1mole of brick =  mass of 1 brick x avagadro number

= 4 kg x 6.022 x 10^23 bricks  = 2.4 x 10^24 kg

No. of moles of bricks have a mass equal to the mass of the earth

= mass of earth / mass of 1 mole of brick

= [ 6 x 10^27 ]  /  [ 2.4 x 10^24 ]

= 2.5 x 10^3

= 2500 moles

Explanation:

Help pls thnk you!!!!

Answers

The amine here is the easiest to spot since there’s only one structure that has a nitrogen atom, which would be the first (the first structure is a primary amine).

The distinguishing functional group of an alcohol is the hydroxy group (—OH). Both the second and third structures have an —OH group, but the —OH in the third structure is part of a carboxyl group (—COOH or —C(=O)OH). A carboxyl group takes priority over hydroxy group. Thus, the second structure would be an alcohol and the third structure would be a carboxylic acid.

That leaves us with the fourth structure, a hydrocarbon with a halogen substitutent, or, aptly named, a halocarbon.

What is the total number of joules required to freeze a 10 g sample of water at 0°C?

show work if possible and will give brainliest

Answers

Explanation:

the answer will be 98.4 kJ

As per concept of enthalpy of fusion , 98,397 joules of energy  are required to freeze 10 g of water  at 0°C.

What  is enthalpy of  fusion?

Enthalpy of fusion is defined as the enthalpy change which results from when  a substance changes its state from solid to  a liquid at a constant pressure.Heat of solidification is opposite of enthalpy of fusion.During fusion  there is a phase transition which takes place, from liquid to solid.

The temperature at which the fusion takes place is called as the fusion temperature. This enthalpy is accompanied without any change in temperature.

Enthalpy of fusion  of water=333.55 J/g  . This value is for 1 g of water as per definition,hence for 10 g water enthalpy of fusion is 10×333.55=3335.5 J.

Hence, 3335.5 joules are required for freezing 10 g sample.

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True or false? Covalent molecules are formed when non-metal atoms share electrons with other non-metal atoms.

Answers

Answer:

true

covalent bonds are between non metals and nonmetals. and they are sharing electrons.

BRIANLIEST!!!!!!
Use the mass to calculate the number of moles in a 347.89 g samples of ammonium

Answers

Answer:

20.46 moles

Explanation:

1 mole of NH3 contains 17gm of NH3

so 347.89 gm of ammonia is in,

347.89/17 moles

=20.46 moles

NOTE. There should be ammonia instead of ammonium in question because ammonium is an ion not a compound.

Chromosomes _____. (Choose all that apply)


1.) Are tightly coiled bundles of DNA


2.) Carry many genes


3.) Are found inside the nucleus of eukaryote


4.) Can be used to diagnose genetic disorders


5.) Outnumber genes in a cell

Answers

Answer:

1.) Are tightly coiled bundles of DNA

2.) Carry many genes

3.) Are found inside the nucleus of eukaryote

4.) Can be used to diagnose genetic disorders

Explanation:

A chromosome is a thread-like structure made up of DNA. The chromosomes are made of DNA which are tightly coiled around protein.

Chromosomes carry hundreds and thousands of genes. The number of genes in a cell outnumbers the number of chromosomes.

In eukaryotic cells, all the chromosomes are found inside the nucleus of eukaryote.

The chromosomes and DNA can be examined so as to diagnose genetic disorders.

Plz help I need the answer now!! Which statement is best supported by the evidence on the map?
A. Oil is produced mostly in the southern part of Africa.
B. Gold is found in every country in Africa.
O
C. Iron ore is found mostly in northern Africa.
D. Each country in Africa has about the same amount of each natural
resource.

Answers

Answer:

I'd say C. You can eliminate the rest of the answers and get C. Most of the iron is found up North on the map.

Explanation:

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