Could somebody please help this is really hard

Answer:

One orbital

Explanation:

There is  only one orbital in the first energy level of any atom of an element.

Electrons present in an atom revolve in different orbits which are stationary states and are also called as energy levels. The energy levels are numbered as integers which are also called as principal quantum numbers.

Energy of the stationary state is given as E= -R

1/n² where R

is the Rydberg's constant. When an electron is excited, and it moves from lower to higher energy levels there is absorption of energy, while when it moves from higher energy level to lower energy level it radiates or gives out energy in the form of radiation.

They can also be defined as the distances between electron and nucleus of an atom . Electrons present in K energy level have least energy .Energy level diagrams are studied to understand nature of bonding , placement of electrons in orbits and and elemental behavior under certain conditions.

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Answer:

None

Explanation:

Numbers can only be significant in three ways.

1) Non-zero numbers

2) Zeroes between non-zero numbers

3) Trailing zeroes in a decimal. Only counts if there is a decimal point.

Since the zeroes are not trailing or located between two non-zero digits, there are no zeroes in 0.0079.

There are three zeros in the  0.0079 significant number value and they are not significant too.

The significant figures are the minimum numbers from zero to nine and which are use to represent the number which results are uncertain and cannot be round off.

Starting zeros are not significant, decimal is not a significant figure, ending zeros ae also not significant and ending zeros without decimal is not a significant figure.

Therefore, there are three zeros in the  0.0079 significant number value and they are not significant too.

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Answer:

All of these are true

Explanation:

A buffer solution in chemistry is a solution that resists changes in pH when an acid or base is added to it. It is a solution that contains a weak acid and its conjugate base (anion) or a weak base and its conjugate acid.

A buffer is able to resist a change in pH due to the conjugate base and conjugate acid of the weak acids and bases contained in them respectively. The conjugate base/acid are present in an equilibrium quantity with their acid/base counterparts and help to neutralize or react with any additional H+ or OH- from an acid or base added to their solution.

However, when a strong acid or base is added to the buffer solution, there is only a slight change which practically does not change the pH of the solution.

Hence, all of the above options about a buffered solution is true.

On seeing the given options, it is clear that all the options are correct.

A solution, which resists the change in pH upon the supplementation of an acidic or basic components is known as a buffer.

The following are the characteristics of buffer:

Thus, all the given statements are true.

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Answer:

Yes

It is an organic chemical compound

Its formula is [tex]C_6H_6[/tex]

Explanation:

Answer:

The options to the question is incomplete, it should contain

D-glucose

1. Amylose- Unbranched, D-glucose, a-1,4-glycosidic

2. Cellulose- Unbranched, D-glucose, B-1,4-glycosidic

Explanation:

Amylose is one of the two polymeric components of starch, the other being amylopectin. Amylose is a polymer, made up of glucose monomers. In the structure of amylose, it is a linear (unbranched) chain of D-glucose subunits connected by α-1,4-glycosidic bonds.

On the other hand, cellulose is another polymer of glucose that makes up the cell wall of plant cells, conferring rigidity on it. It is a complex carbohydrate made up of many glucose units. Cellulose is an unbranched (linear) chain of D-glucose units connected by B-1,4-glycosidic bonds.

Answer: The options are incomplete .

The correct one is D-glucose .

A. Amlyose is Unbranched, D-glucose,

connected by -1,4-glycosidic bond.

2. Cellulose is Unbranched chain D-glucose, connected by B-1,4-glycosidic bond

Explanation:

AMYLOSE is a polysaccharide that is made up of D glucose units which is connected by alpa 1, 4 glycosidic bond. It has a tight helical structure. It is a resistant starch that is not easily digested . It is an important animal digestive storage.

Cellulose is a polysaccharide also made up of D glucose and connected by beta 1,4 glycosidic bonds. cellulose . It is the major composition of plant cell walls. It give rigidity and strength to the cell wall.

Answer:

a

Explanation:

To solve this we must be knowing each and every concept related to  black hole. Therefore, the correct option is option A among all the given option.

A huge star's demise can result in the formation of a black hole. Such a star's core gravitationally collapses inward onto itself near the end of its existence when its internal thermonuclear fuels run out, destroying the star's outer layers in the process.

The dying star is compressed to a point with zero volume or infinite density known as the singularity by the heavy burden of component matter crashing in from all directions.  Astronomers can't take a picture of a black hole because gravity is so strong that even light cannot escape a black hole.

Therefore, the correct option is option A.

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Answer:

C8H18

Explanation:

To be honest I feel like there is more than one answer but this is the answer I got. You calculate how much is left of carbon and hydrogen in order to balance the equation on the left. Once you got the value you just put it into a polynomial structure and you will get the answer above.

Answer:

it looks like the answer that your looking for is B.

Answer:

B may be the answer.

Explanation:

Answer:

[tex]\large \boxed{\mathrm{view \ explanation}}[/tex]

Explanation:

The periodic table of elements is a table consisting of elements arranged by atomic number and properties. There are a total of 118 elements discovered.

Answer:

Periodic table of element is the tabular display of chemical elements which are arranged by atomic numbers, electron configuration and recurring chemical properties

Explanation:

If an astronaut travels to Mars, the mass of the astronaut will decrease on Mars when she arrives. The correct option is B.

The force of gravity is a force that is responsible for the presence of everything object and human in their place. It gives weight to an object. Without gravity, everyone will be floating in the air.

The force of gravity is different in different places. Like on the earth, there is a strong force of gravitation. On the moon, there is the less gravitational force. In mars, there is less gravitation force than on earth.

Because there is less gravitational force on Mars than on the earth, so the weight of the astronaut will be lower on Mars than on the earth.

Thus, the correct option is B. The mass of the astronaut will decrease on Mars.

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Answer:

Dependent and independent variables are variables in mathematical modeling, statistical modeling and experimental sciences. Dependent variables receive this name because, in an experiment, their values are studied under the supposition or hypothesis that they depend, by some law or rule (e.g., by a mathematical function), on the values of other variables. Independent variables, in turn, are not seen as depending on any other variable in the scope of the experiment in question; thus, even if the existing dependency is invertible (e.g., by finding the inverse function when it exists), the nomenclature is kept if the inverse dependency is not the object of study in the experiment. In this sense, some common independent variables are time, space, density, mass, fluid flow rate[1][2], and previous values of some observed value of interest (e.g. human population size) to predict future values (the dependent variable)[3].

Of the two, it is always the dependent variable whose variation is being studied, by altering inputs, also known as regressors in a statistical context. In an experiment, any variable that the experimenter manipulates[clarification needed] can be called an independent variable. Models and experiments test the effects that the independent variables have on the dependent variables. Sometimes, even if their influence is not of direct interest, independent variables may be included for other reasons, such as to account for their potential confounding effect.

Explanation:

Answer:

Buoyancy.

Explanation:

Buoyancy is a force created by the water that is displaced by an object. It is directly proportional to the amount of water that is being displaced by an object.

Hence, the greater the amount of water an object displaces; the greater is the force of buoyancy pushing the object up.

The buoyancy of an object is given by the formula;

[tex]Fb = pgV\\\\But, V = Ah\\\\Hence, Fb = pgAh[/tex]

Where;

Fb = buoyant force of a liquid acting on an object.

g = acceleration due to gravity.

p = density of the liquid.

v = volume of the liquid displaced.

h = height of liquid (water) displaced by an object.

A = surface area of the floating object.

The unit of measurement for the buoyancy of an object is Newton (N).

Answer:

α-ketoglutarate; oxaloacetate

Explanation:

In the malate aspartate shuttle, glutamate is converted to α-ketoglutarate in the mitochondria by the enzyme glutamate dehydrogenase while aspartate is converted to oxaloacetate in the cytosol by the enzyme aspartate aminotransferase.

An important enzyme in the malate aspartate shuttle, is malate dehydrogenase. In the shuttle system, it is present in the mitochondria and in the cytosol and catalyzes the enzymatic reaction in opposite direction.

Answer:

true

Explanation:

Answer:

Affinities

Explanation:

Chromatography is a laboratory technique used for separation of mixture.

In chromatography, the separation is based on different affinities of components in different phases of matter (mobile phase and stationary phase). Different chemical species have different affinities that is the electronic property of the chemical species and form bond with stationary phase.

Hence, the correct option is "Affinities".

Answer:

1. b

2. a

Explanation:

1. The density of an object represents the mass per unit volume of the object. A density of 0.45 g/mL means that 1 mL of the object weighs 0.45 g, 1.000 g/mL means 1 mL weighs 1 g, etc.

A density of 35,885 g/mL means that 1 mL of the object weighs 35,885 g. This is a ridiculously high amount of weight for an object with a volume of 1 mL and seems not reasonable. It is highly unlikely that such a substance exists in nature.

2. Considering the fact that only rock would sink in water of all the substances from a - d, it thus means that rock would have the greatest density. Oil, oxygen, and ice will all float on water, meaning that they are less dense than water.

Answer:

The volume of [tex]7.2\times 10^{-4}\ m^3[/tex] is equal to 720 cm³.

Explanation:

We know that,

1 m = 100 cm

We need to convert [tex]7.2\times 10^{-4}\ m^3[/tex] to cm³.

Also,

1 m³ = 10⁶ cm³

To convert  [tex]7.2\times 10^{-4}\ m^3[/tex] to cm³, the step is as follows :

[tex]7.2\times 10^{-4}\ m^3=(7.2\times 10^{-4}\times 10^6 )cm^3\\\\=720\ cm^3[/tex]

So, [tex]7.2\times 10^{-4}\ m^3[/tex] is equal to 720 cm³.

Answer:

Boyle's Law

Explanation:

Boyle's Law states that the volume of a gas is inversely proportional to the pressure of the gas at constant temperature so if the pressure goes up then the volume goes down and vice versa

By definition of Boyle's law, when the pressure of a confined gas is doubled at a constant temperature, the volume of the gas is reduced by half, this statement is an example of Boyle's law.

But first it is neccesary yo know that an ideal gas is a theoretical gas that is considered to be composed of point particles that move randomly and do not interact with each other.

Gases in general are ideal when they are at high temperatures and low pressures.

On the other side, the gas laws are a set of chemical and physical laws that allow determining the behavior of gases in a closed system. The parameters evaluated in these laws are pressure, volume, temperature, and moles.

Finally, Boyle's law is one of the gas laws that relates the volume and pressure of a certain amount of gas kept at constant temperature.

Boyle's law states that the pressure of a gas in a closed container is inversely proportional to the volume of the container, when the temperature is constant.

This means that if the pressure increases, the volume decreases, while if the pressure decreases, the volume increases.

In summary, when the pressure of a confined gas is doubled at a constant temperature, the volume of the gas is reduced by half, this statement is an example of Boyle's law.

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Answer:

D:Cells

Explanation:

A cell is a the smallest unit of a living thing. A living thing whether made up of one cell which is Bacteria and a living thing whether made up of many cells which is Humans

Answer:

[tex] \boxed{ \bold{ \huge{ \bold{ \blue{ \sf{cell}}}}}}[/tex]

Option D is the correct option

Explanation:

[tex] \underline{ \bold{ \underline{ \huge{ \sf{cell}}}}}[/tex]

The bodies of all plants and animals are made up of basic units. These basic units are called cells . Cells carry out different life activities like respiration , growth , digestion, excretion etc. All living organisms are made up of cells. Cells are like the bricks of a house. Cells are also called the building blocks of organisms. They are known as the basic structural and functional units of life . They are the smallest unit of life. Cells were discovered by an English Scientist Robert Hooke in 1665 AD . Cells are very small. We cannot see them with our names eyes. We use an instrument called microscope to see them. The shapes of cells vary. However, cells may be oval , round , tabular, branched , cylindrical or irregular in shape. Similarly , the size can vary from very small to large. Usually, the diameter of cells ranges from 0.5 micron to 151 microns.

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Since we are going from a larger unit to a smaller unit, we multiply.

So we multiply 1.25 by the conversion factor, which is 1,000.

This gives us 1,250 grams

The sun is made up of two main elements, hydrogen and helium.

Answer:

please mark my answer brainliest

Explanation:

its carbon monoxide

.....

Answer:co

Explanation:the compounds is carbon monoxide and it is found in fired coal it is poison for a human and it may cause death .

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Answer:

Explanation:

Density of a substance is given by

From the question

mass of the wood = 180 g

Since the wood is a cuboid we can find the volume using the formula

Volume = length × width × height

From the question

length = 10cm

width = 6 cm

height = 4 cm

Volume = 10 × 6 × 4 = 240 cm³

Substitute the values into the above formula and solve for the Density

That's

We have the final answer as

Hope this helps you

Answer:

separation of a liquid mixture into fractions differing in boiling point (and hence chemical composition) by means of distillation, typically using a fractionating column.

separation of a liquid mixture into fractions differing in boiling point (and hence chemical composition) by means of distillation, typically using a fractionating column.

Explanation:

A force of 52 N acts upon a 4 kg block sitting on the ground. The acceleration of the object is  13 m/s².

The rate at which velocity changes is called acceleration. Acceleration typically indicates a change in speed, but not necessarily. An item that follows a circular course while maintaining a constant speed is still moving forward because the direction of its motion is shifting.

An object's motion is altered by a net force; the larger the net force, the greater the acceleration. To accelerate at the same rate as less massive objects, higher net forces are needed.

The formula F=ma connects force and acceleration. The letters "F," "m," and "a" stand for force, mass, and acceleration, respectively. A push or pull that one object can apply to another is known as force. The pace at which an object's speed changes is known as acceleration.

Formula for acceleration is

a = f / m

Acceleration = force / mass

= 52N / 4kg

= 13 m/s²

Thus, The acceleration of the object is  13 m/s².

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Answer:

The resulting liquid at the top is the plasma.

Explanation:

This question seeks to compare the difference between the methods of preparation of plasma and that of serum.

To obtain serum from a blood sample, the blood sample is collected in a plain bottle (usually red capped) and the blot is allowed to clot by leaving it standing/alone for about 15 - 20 minutes after collection. This clotted blood is then centrifugated at 2000 - 3000 revolution per minutes (rpm) for 10 minutes. The liquid at the top after centrifugation here is the serum.

In preparing plasma, the blood sample is collected in a bottle that has anticoagulant like the EDTA bottle (which contains an anticoagulant called EDTA) and then inverted slightly about 7 times to allow the EDTA mix with the blood. This blood sample is then centrifugated at 2000 - 3000 for 15 mins. The resulting liquid at the top is the plasma.

Answer:

Explanation:

1. diffusion is a physical process when there is random motion of molecules by which there is a net flow of matter from a region of high concentration to a region of low concentration.

2. Osmosis is the diffusion of water where molecules of water move passively (without energy) from high concentration to low concentration. eg: the way water rushes into a sponge.

3. Active transport moves particles from low to higher concentration. The difference between diffusion and active transport is diffusion does not require energy (eg: oxygen moving from the airways to the lungs - there is very little oxygen in the lungs but lots in the air).  whereas active transport does require energy (eg: when plants take up nutrients from the soil. The soil does not have a large concentration of nutrients, but the plant does)