Researchers are studying lichens growing on trees in a forest ecosystem. At the
beginning of the study, the researchers identified twelve lichen species in the forest.
Later, a forest fire happened in the study area. The researchers returned to the area and
found only six lichen species.
Which inference is best supported from the researchers' observations?

Answer:

c. Absolute dating

Explanation:

Absolute dating is a mathematical process that is still used today by traditional archaeology to determine the chronological age of a given discovery. This type of dating provides an era or time interval expressed in numbers. This system would therefore be in contrast with relative dating, which positions the events concerning a known reference but without ascertaining the annual difference between the elements taken into consideration.

When we talk about absolute dating we are talking about four different systems:

Answer:

c

Explanation:

Answer:

The nucleus and electrons the electrons orbit around the nucleus.

Explanation:

Answer:

nucleus and electrons

Explanation:

nucleus in the middle of the atom containing protons and nuetrons and the outer region contains the electrons

Answer:

Wait so is there a amount of sentences that you have to write

Answer:

The Answer is D

Explanation:

Answer:

the tree branch is puching up on his foot

Answer:

14660.75 kJ.

Explanation:

We are given from the question above that the pressure inside is represented by this equation:

P = Po + C(1-(D1/D))(D1/D).

Thus, P = 100 + C (1 - 1/4) (1/4). Therefore, P  which is = 400 is;

400 = 100 + C (1 - 1/4) (1/4).

Hence, C = 1600. And the equation can be written as P = 100 + 1600 (1 - (D1/D))(D1/D).

The work done during the entire process, w = (work done during the process 1 to 2) + (work done duringbthe process 2 to 3 ).

Therefore, work done during the process 1 to 2 = P(V2 + V1) = 100( π/6 - 0).

{NB: V2 is gotten from π/6 × D^3. Where D^3 = 1. }

Hence, work done during the process 1 to 2 = 52.36 kJ.

So, the work done duringbthe process 2 to 3 ) is going to be the integration of PdV. Where P = 100 + 1600 (1 - (D1/D))(D1/D) and dV = π/2 D^2 dD. Taking the upper and the lower limit as 4 and 1 respectively.

After the integration (kindly check attached picture for the process) the work done duringbthe process 2 to 3  = 14.61 × 10^3 kJ.  

Therefore, The work done during the entire process, w = (work done during the process 1 to 2) + (work done duringbthe process 2 to 3 ).

The work done during the entire process, w = 52.36 kJ + 14.61 × 10^3 kJ.   = 14660.75 kJ.

Answer:

B

Explanation:

I may be wrong sorry...

The Protons and Neutrons are in the Nucleus of the Atom, the Atomic Clouds contain the Electrons.

Answer: A. protons in the atom

Explanation: I just took the test and got a 100% so this should be right. Unless the question is worded differently than mine then it should be right. Hope this helps :)

Answer:

A

Explanation:

Answer:

sorry I don't know the ans.. I'm truly sorry

Answer:

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\ [/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

[tex]n = \frac{3.75 \times {10}^{23} }{6.02 \times {10}^{23} } = \frac{3.75}{6.02} \\ = 0.6229235...[/tex]

We have the final answer as

Hope this helps you

Answer:

You can use the Boyles Law formula

P1V1 = P2V2

Substitute what you have and solve for the new volume. There is no need to do any conversions:

730mmHg * V1 = 719mmHg* 1820mL

V1 = 719mmHg* 1820mL  / 730mmHg

V1 = 1792mmHg

The correct answer should have only 2 significant figures: Volume = 1800mL

Explanation:

hope that this helps

The volume of the helium at 752 mmHg is 1740 ml and  the pressure, in mmHg, if the volume is changed to 345 mL is 3792 mmHg.

Pressure is defined as the force applied perpendicular to an object's surface per unit area over which that force is dispersed.

It is also defined as the physical force exerted on an object.

(a) The volume of the helium at 752 mmHg

P1V1 = P2V2

719 mmHg x 1820 ml = 752 mmHg x V2

V2 = 719 mmHg x 1820 ml / 752 mmHg

V2 = 1740 ml  

(b) The pressure, in mmHg, if the volume is changed to 345 mL

719 mmHg x 1820 ml = P2 x 345 ml

P2 = 719 mmHg x 1820 ml / 345 ml

P2 = 3792 mmHg

Thus, the volume of the helium at 752 mmHg is 1740 ml and  the pressure, in mmHg, if the volume is changed to 345 mL is 3792 mmHg.

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Answer:

57.0kJ/mol is ΔH of the reaction

Explanation:

The reaction is:

1/2 Ba(OH)₂ + HCl → 1/2 BaCl₂ + H₂O + ΔH.

Where  ΔH is the heat of reaction per mole of water.

Moles of water produced are equal to moles of HCl that are:

70.0mL = 0.070L * (0.640mol / L) = 0.0448moles HCl = Moles of water produced.

Now, heat produced is determined using coffee-cup calorimeter equation:

Q = m×ΔT×C

Where Q is heat released

m is mass of solution (70mL + 70mL = 140mL = 140g -Density of 1g/mL-)

ΔT is change in temperature (27.36°C - 23.00°C = 4.36°C)

And C is specific heat of the solution (4.184J/gK)

Replacing:

Q = 140g×4.36°C×4.184J/gK

Q = 2553.9J

This is the heat released when 0.0448 moles of water are produced, that means ΔH is:

2553.9J / 0.0448moles

ΔH = 57000J/mol =

Answer:

To give non expensive spoons the appearance and the chemical resistance of the expensive ones.

Explanation:

Companies are cheap and under strict guidelines. This is their loophole.

Electroplating is the coating of metals by the process of hydrolysis. Metallic spoons are electroplated with silver to give an expensive appearance and chemical resistance.

Electroplating has been known as the electrochemical deposition of the metal on another solid metallic substrate by the process of hydrolysis or cation reduction through electric current.

This process is used to coat metals to prevent them from getting corroded. Also, it has been used to give a decorative and expensive look to ordinary metal.

The metallic spoons are electroplated with silver metal to make them look expensive and rich. The silver moves from the anode towards the cathode where the spoon is in the presence of the current.

Therefore, the metals are electroplated by silver for an expensive and rich look.

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Answer:

An object floats when the weight force on the object is balanced by the upward push of the water on the object. ... If the weight force down is larger than the upward push of the water on the object then the object will sink. If the reverse is true then the object will rise – rising is the opposite of sinking.

Explanation:

Take what you will from this.

Answer:

Wood, rubber, plastic, egg, palm leaves, styrofoam, and some types of natural rocks too!

Answer:

this is so u can give him brainliest, he deserves it

Explanation:

2.22 is correct

Answer:

V2 = 0.98mL

Explanation:

Using Charles' law equation which I as follows:

V1/T1 = V2/T2

Where;

V1 = initial volume (mL)

T1 = initial temperature (K)

V2 = final volume (mL)

T2 = final temperature (K)

Based on the information provided in this question; V1 = 0.80 mL, V2 = ?, T1 = 23°C, T2 = 88°C

Temperature in °C must be converted to Kelvin

T1 (K) = 23°C + 273 = 296K

T2 (K) = 88°C + 273 = 361K

Hence, using V1/T1 = V2/T2

0.80/296 = V2/361

296 × V2 = 0.80 × 361

296V2 = 288.8

V2 = 288.8/296

V2 = 0.9756

V2 = 0.98mL

Answer:

the answer is a

Explanation:

Voltage can be thought of as the pressure pushing charges along a conductor, while the electrical resistance of a conductor is a measure of how difficult it is to push the charges along.

Answer:

Solubility ≡ 62.5 ⋅ g ⋅ 100 ⋅ m L − 1

Explanation:  We want  Concentration = Mass of solute  100 mL volume of solvent .

We make the reasonable assumption that the volume of solution is equal to  40 ⋅ m L

Explanation:

Answer:

62,5 g/l

Explanation:

Concentration = m(NaCl) / V(H2O)

Firstly, we change ml to l, so 400 ml becomes 0,4 l.

Divide 25 by 0,4 and you get 62,5 g/l.

Answer:

The equation to this question is unclear. The equation is as follows:

CO + H2O ---> CO2 + H2

The substance classified as an element is H2.

Explanation:

An element is a substance composed of atoms of the same type. It is the simplest chemical substances that cannot be broken down by any chemical reaction. According to this question showing a chemical equation that produces fuel for certain cars:

CO + H2O ---> CO2 + H2

H2 is the substance that represents an element because it is made up of two atoms of hydrogen to form a molecule. Other substances in the reaction like (CO, CO2, H2O) are made up of two or more different atoms, hence, they are compounds not elements.

The substance represented in the given chemical equation which is classified as an element is: J. [tex]H_2[/tex]

An element can be defined as a pure substance which comprises atoms with the same atomic number (number of protons) in its atomic nuclei.

Basically, an element is any pure substance that can't be broken down, decomposed or transformed into simpler substances by chemical or physical means.

In Chemistry, some examples of an element include the following:

                                  [tex]CO + H2O --> CO_2 + H_2[/tex]

From the above chemical equation, the substance which is classified as an element is hydrogen ([tex]H_2[/tex]).

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Water is known as the universal solvent because it can dissolve almost all ionic compounds due to its polarity that is having partially charged ends.

A polar compound is having the partially charged ends, where the shared pair of electrons are attracted  towards the more electronegative atom, and thus have partial charges on both atoms.

In water, the shared pair of electrons are pulled towards the electronegative oxygen atom and thus O acquires a negative charge and H gets a positive charge. These charged ends are active to attack other reagents and forms hydrogen bonds with other electronegative atoms of ionic bond.

In this way water bonds to the ionic compounds and gets them easily dissolved.  Hence, option C i.e., have partially charged end is correct.

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Answer:

Naming Compounds

Naming Ionic Compounds

An ionic compound is named first by its cation and then by its anion.

LEARNING OBJECTIVES

Convert between the chemical formula of an ionic compound and its name

KEY TAKEAWAYS

Key Points

Most cations and anions can combine to form neutral compounds (typically solids under normal conditions) that are usually referred to as salts.

The net charge of an ionic compound must be zero. Therefore, the number of cations and anions in an ionic compound must be balanced to make an electrically neutral molecule.

When naming ionic compounds, the cation retains the same name as the element. The anion’s name is similar to the elemental name, but the ending of the name has been removed and replaced with “-ide.”

If a metallic element has cations of different charges, which cation is used has to be indicated by its suffix (an older method) or by Roman numerals in parentheses after its name in writing (the Stock system ).

Key Terms

Stock system: A system of naming that includes using Roman numerals to indicate the charge on transition metals.

In chemistry, an ionic compound is a chemical compound in which ions are held together by ionic bonds. Usually, the positively charged portion consists of metal cations and the negatively charged portion is an anion or polyatomic ion. Ionic compounds have high melting and boiling points, and they tend to be hard and brittle.

Ions can be single atoms, as the sodium and chlorine in common table salt (sodium chloride), or more complex (polyatomic) groups such as the carbonate in calcium carbonate. But to be considered an ion, they must carry a positive or negative charge. Thus, in an ionic bond, one ‘bonder’ must have a positive charge and the other a negative one. By sticking to each other, they resolve, or partially resolve, their separate charge imbalances. Positive to positive and negative to negative ionic bonds do not occur.

Most cations and anions can combine to form solid compounds that are usually known as salts. The one overriding requirement is that the resulting compound must be electrically neutral: therefore the ions Ca2+ and Br– combine only in a 1:2 ratio to form calcium bromide, CaBr2. Because no other simpler formula is possible, there is no need to name it “calcium dibromide.” CaBr2 can be named using either the Stock method or the older, classic way of naming.

For example, CuCl2 indicates a molecule where one Cu2+ cation associates with two Cl– anions to form a neutral compound. Its systematic name is copper (II) chloride, where copper’s oxidation number is indicated in parentheses. Its older name is cupric chloride.

The Stock Method of Naming

An ionic compound is named first by its cation and then by its anion. The cation has the same name as its element. For example, K+1 is called  the potassium ion, just as K is called the potassium atom. The anion is named by taking the elemental name, removing the ending, and adding “-ide.” For example, F-1 is called fluoride, for the elemental name, fluorine. The “-ine” was removed and replaced with “-ide.” To name a compound, the cation name and the anion named are added together. For example, NaF is also known as sodium fluoride.

If either the cation or the anion was a polyatomic ion, the polyatomic ion name is used in the name of the overall compound. The polyatomic ion name stays the same. For example, Ca(NO3)2 is called calcium nitrate.

For cations that take on multiple charges (typically transition metals), the charge is written using Roman numerals in parentheses immediately following the element name. For example, Cu(NO3)2 is copper (II) nitrate, because the charge of two nitrate ions (NO3−1) is 2(-1) = -2. Since the net charge of the ionic compound must be zero, the Cu ion has a 2+ charge. This compound is therefore, copper (II) nitrate. The Roman numerals in fact show the oxidation number, but in simple ionic compounds this will always be the same as the metal’s ionic charge.

The Old, Classic, or Common Way of Naming

image

Names of some ionic compounds: Common, or trivial, names of compounds are sometimes used in informal conversations between chemists, especially older chemists. Systematic names are formal names that are always used in print.

Since some metallic elements form cations that have different positive charges, the names of ionic compounds derived from these elements must contain some indication of the cation charge. The older method uses the suffixes -ous and -ic to denote the lower and higher charges, respectively. In the cases of iron and copper, the Latin names of the elements are used (ferrous/ferric, cuprous/cupric). This system is still used, although it has been officially supplanted by the more precise, if slightly cumbersome, Stock system. In both systems, the name of the anion ends in -ide.

Explanation:

Explanation:

Chemistry is the scientific discipline involved with elements and compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a reaction with other substances.

Answer:

Capable of being hammered out thin

Explanation:

, as certain metals; malleable. capable of being drawn out into wire or threads, as gold. able to undergo change of form without breaking.

Answer:

It can cause a reflection

Explanation:

Reflection is when incident light (incoming light) hits an object and bounces off. Very smooth surfaces such as mirrors reflect almost all incident light