Which of the following is most helpful for identifying an organism using a dichotomous key?


Its average lifespan


Its sources of food


Its habitat


Its physical structures

Answer:

Due to the presence of 4 valence electrons.

Explanation:

The tetrahedral arrangement of bonds formed by carbon and its relevance In the interaction of biomolecules occurs because the carbon atom has four electrons in their outermost shell and the four hydrogens has one electron each which result is a total of eight electrons distributed in four bonding orbitals making the structure of tetrahedral and the bond angles between these carbon atoms is approximately 109.5 degree.

Answer:

2.14 Na2S + 1.99 HCl ----> 3.20 NaCl + 0.935 H2S

Explanation:

The Balanced equation is

Na2S + 2HCl = 2NaCl + H2S

As we can see -

78.0452 g/mol of sodium sulfide reacts with 2 mole of HCl.

Mass of one mole of HCl = 36.458 g/mol

So, 78.0452 g/mol of sodium sulfide reacts with 2* 36.458 g/mol of HCL to produce 2* 58.44 g of NaCl and 34.1 g/mol of H2S

Thus,

2.14g of sodium sulfide will react with (2* 36.458/78.0452)* 2.14 of HCl

2.14g of sodium sulfide will react with 1.99 g of HCl

2.14 Na2S + 1.99 HCl ----> (2* 58.44/78.0452) *2.14 NaCl + (34.1/78.0452) * 2.14 H2S

2.14 Na2S + 1.99 HCl ----> 3.20 NaCl + 0.935 H2S

Answer:

Lithium Cation is a monovalent cation that is metabolized much like sodium and is important in many cellular functions inside or on the surface of cells. lithium has a single valence electron that is easily given up to form a cation. Because of this, lithium is a good conductor of heat and electricity as well as a highly reactive element, though it is the least reactive of the alkali metals

Answer:

Do you mean acids?

Due to chemical reaction

Explanation:

Acids are only stored in glass containers because glass containers rarely react with any substance.They dont react with acids and prevent chemical reaction so the acids can be kept. If acids were kept in metal containers it would react .

Answer:

.........................................................................................................................................................................................................................................................................................................................................................................................................................................................

Explanation:

If 36g of Al react with 34L of Oz, 0.667 moles of Al2O3 are produced. The correct option is b, 0.667 moles

The mole is a SI unit of measurement that is used to calculate the quantity of any substance.

[tex]\rm 4Al +3O_2 -- > 2Al_2O_3[/tex]

Step1- calculate the moles of aluminum

The mass of Al is 36 g

The molar mass of Al is 27

[tex]\rm Number\;of \;moles= \dfrac{mass}{molar\;mass}\\\rm Number\;of \;moles\;of\;Al = \dfrac{36}{27} = 1.33\;mol[/tex]

Step2- calculate the moles of oxygen

The mass of O₂ is 34 L

[tex]\rm 1 L = \dfrac{1}{22.4 }[/tex]

[tex]\rm Number\;of \;moles\;O_2= \dfrac{34}{22.4} = 1.51[/tex]

The limiting reagent is 1.33 MOL. By the rule of stoichiometry, four moles of Al produced 2 moles of Al.

[tex]\rm \dfrac{1.33}{2} = 0.665 \;moles[/tex]

Thus, the correct option is b. 0.667 moles.

Learn more about moles

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Answer: The statement collisions only result in a reaction if the particles collide with a certain maximum energy called the activation energy of the reaction, is false.

Explanation:

Activation energy is the minimum amount of energy required to initiate a chemical reaction.

So, when activation energy for a reaction is lower then molecules with lower energy can also participate in the reaction. As a result, more number of collisions will take place due to which an increase in the rate of reaction will takes place.

When activation energy for a reaction is larger then molecules with higher energy will not be able to participate in the reaction. As a result, less number of collisions will take place due to which a decrease in rate of reaction will occur.

Therefore, we can conclude that the statement collisions only result in a reaction if the particles collide with a certain maximum energy called the activation energy of the reaction, is false.

Answer:

true

Explanation:

particularly must collide with energy equal to or greater the

Answer:

the first country that uses paper currency is china

the first use of paper currency can be traced back to the year 806 AD in China where they were used as flying currency

Answer:

Q = 1455.12 Joules.

Explanation:

Given the following data;

Mass = 300 grams

Initial temperature = 22.3

Final temperature = 59.9°C

Specific heat capacity = 0.129 J/gºC.

To find the quantity of energy;

[tex] Q = mcdt[/tex]

Where,

Q represents the heat capacity.

m represents the mass of an object.

c represents the specific heat capacity of water.

dt represents the change in temperature.

dt represents the change in temperature.

dt = T2 - T1

dt = 59.9 - 22.3

dt = 37.6°C

Substituting the values into the equation, we have;

[tex] Q = 300*0.129*37.6 [/tex]

Q = 1455.12 Joules.

Answer:

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Explanation:

Answer: A long-term environmental change is... ice age, deforestation, urbanization, Earth's orbit, Sun's intensity, global Warming, radioactive waste/pollution. Extinction of species could happen to anyone of the food webs in a long term change.

Explanation:

Answer:

Hydrologists study how water interacts with the earth's crust. For example, they may study how rainfall and snowfall cause erosion, create caves, percolate through soil and rock to become groundwater, or eventually reach the sea.Hydrologists strive to improve water quality and increase our access to water so that we can continue to make use of it in all the ways that are necessary to our lives. A hydrologist measures the stream flow in a tributary to the Coeur d'Alene River. layers of gases surrounding a planet or other celestial body

Answer: A 13.88 mL of the concentrated acid would be required to make 250. mL of a 1.00 M [tex]H_{2}SO_{4}[/tex] solution.

Explanation:

Given: [tex]M_{1}[/tex] = 18.0 M,     [tex]V_{1}[/tex] = ?

[tex]M_{2}[/tex] = 1.00 M,         [tex]V_{2}[/tex] = 250 mL

Formula used to calculate the volume of concentrated acid is as follows.

[tex]M_{1}V_{1} = M_{2}V_{2}[/tex]

Substitute the values into above formula as follows.

[tex]M_{1}V_{1} = M_{2}V_{2}\\18.0 M \times V_{1} = 1.00 M \times 250 mL\\V_{1} = \frac{1.00 M \times 250 mL}{18.0 M}\\= 13.88 mL[/tex]

Thus, we can conclude that 13.88 mL of the concentrated acid would be required to make 250. mL of a 1.00 M [tex]H_{2}SO_{4}[/tex] solution.

Answer:

0.333J/g°C is the specific heat of the metal

Explanation:

The heat that the metaal gives is equal to the heat that water is absorbing. The equation is:

S(metal)*ΔT(metal)*Mass(metal) = S(H2O)*ΔT(H2O)*Mass(H2O)

Where S is specific heat, ΔT is change in temperature and mass the mass in grams of the metal and water.

Replacing:

S(metal)*(100.0°C-27.2°C)*125.0g = 4.184J/g°C*(27.2°C-24.3°C)*250.0g

S(metal) = 4.184J/g°C*(27.2°C-24.3°C)*250.0g / (100.0°C-27.2°C)*125.0g

S(metal) = 0.333J/g°C is the specific heat of the metal

Answer:

0.73 and yes

Explanation:

The answers are 0.73 and yes! <3 ^-^

Answer:

d. 3.0

Explanation:

First we calculate the pOH of the solution, using the following formula:

Using the pOH we can calculate the pH of the solution, keeping in mind the relationship between pH and pOH:

The answer is option d.

Answer: Option C is correct

Grams solid x mol/g * A Hfusion

Explanation:

This is because from fusion is associated to melting and this is a process where solid particles or substances goes through transition phase and turn to liquid.

There for the stoichiometry is used to calculate energy absorbed when solid mass melt with the formula Grams solid x mol/g * A Hfusion.

Answer: a

Explanation:

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Interspecific competition often leads to extinction. The species that is less well adapted may get fewer of the resources that both species need. As a result, members of that species are less likely to survive, and the species may go extinct.

Answer:

Chemical reactions and physical transformations do not create or destroy mass in an isolated system, according to the law of conservation of mass. The mass of the products in a chemical reaction must equal the mass of the reactants, according to the conservation of mass law. The law of conservation of mass can be used to solve for unknown masses, such as how much gas is consumed or produced during a reaction.

Answer:

see image

Explanation:

let me know if you have any questions

Answer:

It measures large earthquakes far from the seismograph.

Explanation:

It uses a seismograph to measure earthquakes far from the seismograph where seismic waves are used to determine the magnitude of an earthquake.

Answer: d. It increases in magnitude with an increase in size of seismic waves.

Explanation:

From what I know personally from learning about this type of subject in the past is that children are more susceptible to the effects of toxic substances more than adults are, certain scientific data specifically indicate that children actually are for all intents and purposes more basically susceptible to toxic exposure than adults because they for the most part have proportionally definitely more intake of food contaminants, basically active developmental processes, basically multiple exposure pathways and really susceptible kind of socio-behavioral activities in a particularly major way.

Answer:

here's the answer hope it helps

Answer:

Neutrons and protons

Explanation:

There are three fundamental subatomic particles, these are;neutrons protons and electrons.

Ernest Rutherford successfully showed that every atom does possess a central core that contain positively charged particles (protons) called the nucleus. Chadwick later discovered the existence of neutrons.

Both protons and neutrons are found in the nucleus. Z represents the nucleus of the boron atom and houses the neutrons and protons of the boron atom.

Answer:

2,3-dimetylpentane

Explanation:

.....................

Answer:

The empirical formula of the compound is [tex]C_{0.504}HO_{1.008}[/tex].

Explanation:

We need to determine the empirical formula in its simplest form, where hydrogen ([tex]H[/tex]) is scaled up to a mole, since it has the molar mass, and both carbon ([tex]C[/tex]) and oxygen ([tex]O[/tex]) are also scaled up in the same magnitude. The empirical formula is of the form:

[tex]C_{x}HO_{y}[/tex]

Where [tex]x[/tex], [tex]y[/tex] are the number of moles of the carbon and oxygen, respectively.

The scale factor ([tex]r[/tex]), no unit, is calculated by the following formula:

[tex]r = \frac{M_{H}}{m_{H}}[/tex] (1)

Where:

[tex]m_{H}[/tex] - Mass of hydrogen, in grams.

[tex]M_{H}[/tex] - Molar mass of hydrogen, in grams per mole.

If we know that  [tex]M_{H} = 1.008\,\frac{g}{mol}[/tex] and [tex]m_{H} = 0.2\,g[/tex], then the scale factor is:

[tex]r = \frac{1.008}{0.2}[/tex]

[tex]r = 5.04[/tex]

The molar masses of carbon ([tex]M_{C}[/tex]) and oxygen ([tex]M_{O}[/tex]) are [tex]12.011\,\frac{g}{mol}[/tex] and [tex]15.999\,\frac{g}{mol}[/tex], then, the respective numbers of moles are: ([tex]r = 5.04[/tex], [tex]m_{C} = 1.2\,g[/tex], [tex]m_{O} = 3.2\,g[/tex])

Carbon

[tex]n_{C} = \frac{r\cdot m_{C}}{M_{C}}[/tex] (2)

[tex]n_{C} = \frac{(5.04)\cdot (1.2\,g)}{12.011\,\frac{g}{mol} }[/tex]

[tex]n_{C} = 0.504\,moles[/tex]

Oxygen

[tex]n_{O} = \frac{r\cdot m_{O}}{M_{O}}[/tex] (3)

[tex]n_{O} = \frac{(5.04)\cdot (3.2\,g)}{15.999\,\frac{g}{mol} }[/tex]

[tex]n_{O} = 1.008\,moles[/tex]

Hence, the empirical formula of the compound is [tex]C_{0.504}HO_{1.008}[/tex].

Answer:

160 mL

Explanation: