What do scientists mean when they refer to population

Answers

Answer 1

population is the number of species living in a given area if this is regarding biology or earth studies :)

Answer 2
The number of people

Related Questions

what does pen mean?.

Answers

Answer:

P = protons

E = electrons

N = neutrons

remember protons and neutrons (protons are positive and neutrons are neutral as you can already tell by their names) are found at the centre of the nucleus (positive mass). Whilst the electrons (negative) orbit around the shells

How many grams of chlorine are required in order to consume 85g of
sodium?
2 Na +1 C12
+ 2 Naci

Answers

Check the attached photo out...

During a dry compression test, the first puff of the test shows 50 PSI and the maximum reading after 4 strokes is 150 PSI. This indicates A. that the cylinders are good. B. weak piston rings. C. a bad spark plug. D. a hole in the piston.​

Answers

B.. you welcome :) i did this and got it right btw
B) weak piston rings What is compression test?

One of the basic engine-diagnostic procedures that can be run is an engine compression test. All of the cylinders must have the same compression for the engine to run smoothly. There are just three possible ways for air to leak out of an engine and cause compression loss.

Exhaust or intake valve Engine rings (or piston, if there is a hole) An engine's head gasketThe procedures for conducting a compression test

The engine should be warmed to its typical operating temperature before testing in order to achieve the best results. The following procedures should be followed for an accurate compression test:

STEP 1: Dispose of each spark plug. As a result, the engine can be turned up to the same speed. Label all spark plug wires accurately.STEP 2 is to block the throttle open. This enables the engine to pull in the most air possible. Additionally, this step guarantees reliable compression test results.STEP 3 After inserting a compression gauge into a spark plug hole, start the engine. Four compression strokes of engine cranking should be performed in total. A puffing sound is produced after each compression stroke.EXAMPLE-If the ultimate, maximum value is 150 PSI, for instance, the reading following the first puff should be greater than 75 PSI. Low first-puff readings could be a sign of weak piston rings.STEP 4 Keep track of the highest readings, then compare the outcomes.

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How does size affect weight?
(20 points, write at least 5 sentences answer pls thx!)

Answers

Many weight charts have 10 pound increments in each frame size; small, medium, and large. ... Being big-boned or small boned doesn't justify a 20-25 pounds differential from a normal size person. If you are truly convinced you are not overweight just big boned.

atoms of which two elements have combined total of 23 protons​

Answers

Answer:

sodium and magnesium

Explanation:

Sodium,na and magnesium

What is the enthalpy in KJ of reaction for the initial combustion if the delta H for vaporization is 75.75 KJ and the net delta H is -700 kJ?
Write your answer to hundredths, including a negative sign if needed. Do not write the unit.

Answers

Answer:

-775.75

Explanation:

What is the name of this molecule?

Answers

Answer:

pentanoic acid

Explanation:

it has 5 carbon atoms which gives it the parent name pent, and its attached to the ester group

when someone pours milk into this life what is the the role of the coffee
A. Salt
B solvent
C solute
D solution

Answers

B solvent because it is socking in
the answer you are looking for is B I agree

Write and balance the following equation:


zinc (II) nitrate + copper
→ copper (1) nitrate + zinc

Answers

Answer:

This reaction will not occur since copper is less reactive than zinc.

Explanation:

Since copper is located at a lower position in the reactivity series than zinc, there will be no displacement reaction if copper is put into zinc (II) nitrate solution.

Fission and fusion are alike in many ways. However, one difference is
A)
Fusion forms dangerous nuclear waste that is difficult to dispose whereas
fission does not.
Eliminate
B)
Fission is a controllable chain reaction and fusion is not.
Fusion results in a greater product mass whereas fission does not.
D)
Raw materials for fission are cheaper and easy to get.

Answers

Explanation:

Fusion vs Fission

In fission, energy is gained by splitting apart heavy atoms, for example uranium, into smaller atoms such as iodine, caesium, strontium, xenon and barium, to name just a few. However, fusion is combining light atoms, for example two hydrogen isotopes, deuterium and tritium, to form the heavier helium. Both reactions release energy which, in a power plant, would be used to boil water to drive a steam generator, thus producing electricity.

Answer:

B

Explanation:

i did this

How many moles of CO2 are in 58.5 g of carbon dioxide?
4 points
2.72 mol CO2
1.07 mol CO2
3.42 mol CO2
1.83 mol CO2

Answers

Just divide 58.5 grams by the molar mass of CO2. Use the periodic table to find the masses of C and O

Molar mass of CO2 = 12.01(1) + 16(2) = 12.01+32 = 44.01 g/mol

mol of CO2 = 58.5g/44.01 g/mol = 1.329 mol = 1.33 mol with correct sig figs

Classify the following as either an element, compound, homogeneous mixture or
heterogeneous mixture:
milk

Answers

Answer:

Heterogeneous

Explanation:

Milk seems to be homogeneous mixture but actually milk is a heterogeneous mixture and a colloid solution.

What is the pressure exerted by 2.5 mol of gas with a temperature of 25 Celsius and a volume of 12.2 L

Answers

Answer:

5.01 atm

Explanation:

To answer this question, we're going to use the PV=nRT equation, where in this case:

P = ?V = 12.2 Ln = 2.5 molR = 0.082 atm·L·mol⁻¹·K⁻¹T = 25 °C ⇒ 25 + 273.16 = 298.16 K

We input the data:

P * 12.2 L = 2.5 mol * 0.082 atm·L·mol⁻¹·K⁻¹ * 298.16 K

And finally solve for P:

P = 5.01 atm

The mass of a salt in grams that will dissolve in 100 mL of water.

____________ A solution that has dissolved the maximum amount of a compound at a given temperature. Any further addition of salt will remain undissolved.
_________ The product of the molarities of the dissolved ions, raised to a power equal to the ion's coefficient in the balanced chemical equation.
__________ A decrease in the solubility of an ionic compound as a result of the addition of a common ion.
__________ The maximum number of moles of a salt that will dissolve in 1 L of solution.

a. A decrease in the solubility of an ionic compound as a result of the addition of a common ion.
b. The mass of a salt in grams that will dissolve in 100 mL of water.
c. A solution that has dissolved the maximum amount of a compound at a given temperature. Any further addition of salt will remain undissolved.
d. The product of the molarities of the dissolved ions, raised to a power equal to the ion's coefficient in the balanced chemical equation.
e. The maximum number of moles of a salt that will dissolve in 1 L of solution.

Answers

Answer:

Solubility  : The mass of a salt in grams that will dissolve in 100 mL of water

Saturated solution : A solution that has dissolved the maximum amount of a compound at a given temperature. Any further addition of salt will remain undissolved

Solubility product constant :The product of the molarities of the dissolved ions, raised to a power equal to the ion's coefficient in the balanced chemical equation

Common ion effect : A decrease in the solubility of an ionic compound as a result of the addition of a common ion

Molar solubility : The maximum number of moles of a salt that will dissolve in 1 L of solution

Explanation:

Solubility is expressed usually as the mass of solute per 100 grams or 100 ml of solvent.

Molar solubility of a solid is expressed as the concentration of the dissolved solid in a saturated solution.

Solubility product constant is defined as the equilibrium constant in which a solid ionic compound is dissolved to produce its ions in solution. It is represented as  

The common-ion effect is the decrease in solubility of a sparingly soluble salt by the addition to the solution of a soluble compound with an ion in common with the precipitate.

Saturated solution is defined as the solution in which no more solute particles can be dissolved in the solvent.

is chemical energy stored in coal, gas, and oil?

Answers

Chemical energy is energy stored in the bonds of atoms and molecules. Batteries, biomass, petroleum, natural gas, and coal are examples of chemical energy.
It’s All of the above

Consider the reactivity of phenol, bromobenzene, toluene, and nitrobenzene toward electrophilic aromatic substitution.
The most reactive compound is:_____
because the _______ character of the ______ increases the rate of the reaction.
The least reactive compound is ______
because the _______ character of the ________ decreases the rate of the reaction.

Answers

Answer:

The most reactive compound is: Phenol  because the electron donating character of the alcohol group increases the rate of the reaction.

The least reactive compound is nitrobenzene

because the electron withdrawing character of the nitro group decreases the rate of the reaction.

Explanation:

PHENOL-: Any of a group of organic compounds with a hydroxyl (OH) group bound to a carbon atom in an aromatic ring is known as phenol. The word phenol is also the basic name for its simplest member, monohydroxybenzene (C6H5OH), also known as benzenol or carbolic acid, in addition to being the common name for the entire family.ELECTRON DONATING CHARACTER-: Via the carbon atom it is bound to, an electron donating group (EDG) has the net effect of increasing electron density in a molecule. EDGs alter a molecule's reactivity by increasing electron density on neighboring carbon atoms: EDGs make nucleophiles stronger.ALCOHOL GROUP-:Each of a class of organic compounds that have one or more hydroxyl (OH) groups bound to an alkyl group's carbon atom (hydrocarbon chain)is called Alcohol. Alcohols are organic compounds of water [tex](H_2O)[/tex] in which one of the hydrogen atoms has been substituted by an alkyl group, which in organic structures is usually expressed by R.NITROBENZENE-:The organic compound nitrobenzene has the chemical formula [tex](C_6H_5NO_2)[/tex]. It's a pale yellow oil that's insoluble in water and smells like almonds. Greenish-yellow crystals form when it freezes. It is made on a wide scale as a precursor to aniline from benzene. It is sometimes used as a solvent in the laboratory, especially for electrophilic reagents.ELECTRON WITHDRAWING GROUP-: An electron withdrawing group (EWG) is a type of group that reduces electron density in a molecule by bonding to a carbon atom. EWGs alter a molecule's reactivity by reducing electron density on neighboring carbon atoms.NITRO GROUP-: The nitro group is one of the most widely used explosophores (functional groups that combine to form a compound explosive). In addition, the nitro group is a heavy electron-withdrawing group. CH bonds alpha (adjacent) to the nitro group may be acidic due to this property.

What is the concentration of a solution with a
volume of 2.5 liters containing 660 grams of
calcium phosphate Ca3(PO4)2 ?

Answers

Answer:

660gx Imol = 2.1278 mol 310.189 2.5L 1.85 m).

Explanation:

The number of moles of 660 grams of calcium phosphate is 2.127. Then the molarity of the solution of 2.5 liter volume is 0.85 M.

What is molarity ?

Molarity is a common term used to express the concentration of a solution. It is the ratio of number of moles of solute particles to the volume of solution in liters. Hence, its unit is mol/L or molar.

The molarity of a solution is a colligative quantity as well as temperature dependent.

Given,

molar mass calcium phosphate,  Ca₃(PO₄)₂  =310.18 g/mol

Then,

no.of moles of calcium sulphate in 660 g = 660 g/310.18 g/mol = 2.127 moles

volume of solution = 2.5 L

Molarity = no.of moles of solute/ volume of solution in L

M = 2.127 moles/ 2.5 L

   = 0.85 M.

Therefore, the molarity of the given solution is 0.85 molar.

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If 4.0 g of helium gas occupies a volume of 22.4 L at 0 o C and a pressure of 1.0 atm, what volume does 3.0 g of He occupy under the same conditions?

Answers

Answer:

the volume occupied by 3.0 g of the gas is 16.8 L.

Explanation:

Given;

initial reacting mass of the helium gas, m₁ = 4.0 g

volume occupied by the helium gas, V = 22.4 L

pressure of the gas, P = 1 .0 atm

temperature of the gas, T = 0⁰C = 273 K

atomic mass of helium gas, M = 4.0 g/mol

initial number of moles of the gas is calculated as follows;

[tex]n_1 = \frac{m_1}{M} \\\\n_1 = \frac{4}{4} = 1[/tex]

The number of moles of the gas when the reacting mass is 3.0 g;

m₂ = 3.0 g

[tex]n_2 = \frac{m_2}{M} \\\\n_2 = \frac{3}{4} \\\\n_2 = 0.75 \ mol[/tex]

The volume of the gas at 0.75 mol is determined using ideal gas law;

PV = nRT

[tex]PV = nRT\\\\\frac{V}{n} = \frac{RT}{P} \\\\since, \ \frac{RT}{P} \ is \ constant,\ then;\\\frac{V_1}{n_1} = \frac{V_2}{n_2} \\\\V_2 = \frac{V_1n_2}{n_1} \\\\V_2 = \frac{22.4 \times 0.75}{1} \\\\V_2 = 16.8 \ L[/tex]

Therefore, the volume occupied by 3.0 g of the gas is 16.8 L.

The volume occupied by 3.0 g of He is mathematically given as

V2=16.8L

What volume does the 3.0 g of He occupy?

Question Parameters:

If 4.0 g of helium gas occupies a volume of 22.4 L at 0 o C and a pressure of 1.0 atm, what volume does 3.0 g of H

Generally, the equation for the gas equation  is mathematically given as

PV=nRT

When the reacting mass is 3g

n2=3/4

n2=0.75

Therefore

V1/n1=V2/n2

Where

n1=1

[tex]V2=\frac{22.4*0.75}{1}[/tex]

V2=16.8L

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During which process is liquid changed to a gas within the water cycle?

Answers

Answer:

evaporation.

evaporation is the process by which water changes from liquid to a gas or vapor.

A student placed 2 drops of an unknown sample in a test tube and added 2 mL of ethanol to the test tube while mixing gently. They added 2 drops of potassium permanganate reagent to the test tube and mixed the contents of the test tube gently. The initial color was a deep purple but then changed to a yellow color which precipitates as a brown solid. What compound is most likely the unknown

Answers

Answer:

2-propanol

Explanation:

From the given information

2 drops of an unknown sample were said to be placed in a test tube followed by the addition of 2 ml of ethanol then gentle mixing. They then initiate a further addition of  2 drops of potassium permanganate reagent (KMNO₄) to the test tube and mixed the contents of the test tube thoroughly. After adding 2 drops of potassium permanganate reagent, the reagent oxidizes the secondary alcohols(2-propanol) to ketone(i.e acetone) and no further reaction will take place since there are no reactive C-H bonds left. The diagram attached below shows how the reaction proceeds.

WILL MARK B!
Check image
Will increase points but someone answer Because I have an exam please answer ASAP

Answers

Answer:

Bro don't cheat in online exams bro

What is the standard temperature? Express your answer in kelvins to two decimal places.

Answers

Answer:

The standart temperature is 273.15 degrees Kelvin

Explanation:

Answer:

i would say its 0 degrees celcius

Explanation:

explain what you would do expect caesium astatide to look like .will it be soluble in water ?explain your reasoning​

Answers

Answer:

it will not be soluble in water Becoz it can only be

separated by passing it through silver nitrate solution

Explanation:

i hope you understand

The cell wall regulates what enters and exits the cell? True or False

Answers

Answer:

True

Explanation:

Answer:No, the Cell Membrane does I'm pretty sure

Explanation:

Do molecules move faster or slower when energy is transferred in?

Answers

Answer:

In conduction, faster-moving molecules contact slower-moving molecules and transfer energy to them. During conduction the slower-moving molecules speed up and the faster-moving molecules slow down.

Explanation:

- Explain why the term greenhouse effect is used to describe the theory of global
warming.
Does the greenhouse effect affect life on Earth? If yes, explain how?
What are the possible effects of a buildup of greenhouse gases in our atmosphere?

Answers

The greenhouse effect is a process that occurs when gases in Earth's atmosphere trap the Sun's heat. This process makes Earth much warmer than it would be without an atmosphere. It is one of the things that makes Earth a comfortable place to live.

FREE BRAINLIST NEED HELP ASAP

Answers

Answer: F. Electrons

Explanation: hope it helped    .u.

Use the following balanced reaction to solve 1-3:
P4 (s) + 6H2 (g) → 4PH3 (g)

How many grams of phosphorus trihydride will be formed by reacting 60 L of Hydrogen gas with an excess of P4?

Answers

Answer:

60.86 g of PH₃

Explanation:

We'll begin by calculating the number of mole of H₂ that will occupy 60 L. This can be obtained as follow:

22.4 L = 1 mole of H₂

Therefore,

60 L = 60 / 22.4

60 L = 2.68 mole of H₂.

Next, we shall determine the number of mole of PH₃ produced by the reaction of 60 L (i.e 2.68 mole) of H₂. This can be obtained as follow:

P₄ + 6H₂ –> 4PH₃

From the balanced equation above,

6 moles of H₂ reacted to produce 4 moles of PH₃.

Therefore, 2.68 moles of H₂ will react to to produce = (2.68 × 4)/6 = 1.79 moles of PH₃.

Finally, we shall determine the mass of 1.79 moles of PH₃. This can be obtained as follow:

Mole of PH₃ = 1.79 moles

Molar mass of PH₃ = 31 + (3×1)

= 31 + 3 = 34 g/mol

Mass of PH₃ =?

Mass = mole × molar mass

Mass of PH₃ = 1.79 × 34

Mass of PH₃ = 60.86 g

Thus, 60.86 g of PH₃ were obtained from the reaction.

Two trials are run, using excess water. In the first trial, 7.8 g of Na2O2(s) (molar mass 78 g/mol) is mixed with 3.2 g of S(s). In the second trial, 7.8 g of Na2O2(s) is mixed with 6.4 g of S(s). The Na2O2(s) and S(s) react as completely as possible. Both trials yield the same amount of SO2(aq). Which of the following identifies the limiting reactant and the heat released, q, for the two trials at 298 K?
Limiting Reactant q
A. S 30. kJ
B. S 61 kJ
C. Na2O2 30. kJ
D. Na2S2 61 kJ

Answers

Answer:

The answer is "Option C".

Explanation:

Given equation:

[tex]2Na_20_2 (s)+S(s)+2H_2O \longrightarrow 4NaOH(aq)+SO_2(aq)[/tex]

[tex]\to \Delta H^{\circ}_{rxn} (298\ K) = -610 \frac{kJ}{mol}[/tex]

[tex]\to Na_2O_2 \ Mass = 7.8 \ g\\\\ \to Na_2O_2 \ Molar \ mass = 78 \frac{g}{mol}[/tex]

[tex]Na_2O_2[/tex] Has been the reactant which is limited since the two experiments are equal to[tex]Na_2O_2[/tex] for relationship between stress amounts.

[tex]Na_2O_2, n =\frac{Mass of Na_2O_2}{Molar mass of Na_2 O_2}=\frac{7.8 \ g}{78 \frac{g}{mol}} =0.1 \ mol \\\\q=\Delta H^{\circ}_{rxn} \times n = \frac{ -610 \ kJ}{ 2 \ mol \ Na_2 O_2} \times 0.1 \ mol \ Na_2O_2= 30.5 \ KJ\\\\[/tex]

Limiting reactant =[tex]Na_2O_2[/tex]

[tex]q=30.5 \ kJ \approx 30 \ kJ[/tex]

Help this is for marks, who ever answers get brainliest

Answers

Answer:

Coal

Explanation:

thx for points :D

Answer:

Coal

Explanation:

your welcome<3

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