Please help!!!

Perform the following operation
and express the answer in
scientific notation.
9x102: 3x1012

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 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:

8

Explanation:

This is because fluorine has the 9 electrons but because it's an ion it gives out an electron thereby losing an electron...so the electron number is 8

Answer:

8electron

Explanation:

Fluorine has 9electron on its orbit although it loses one weak electron to another strong element during ionization. example: Cl-F

Answer:

structure of argon

Explanation:

The nucleus contains 18 protons ( red) and 22 neutrons (orange). 18 electrons (white) occupy shells ring.

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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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

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:

neutral

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".

a. vinegar

b. Mineral deficiencies in the body can make joint pain worse. Because Vinegar contains the calcium, magnesium, potassium, and phosphorus your body needs, it helps as a supplement and therefore reduces pain.

1. in making fertilisers which are chemical compounds or salts to increase fertility of soil.

2. lithium hydroxide is used in space because of its high absorption of carbon dioxide and the small amount of heat produce by the reaction.

3. Acid rain has a lower pH than "normal" rain . Rain is naturally somewhat acidic with a pH between 5.0-5.5 typically. Acid rain has a pH that is below this: 4.4-4.2

4. lemon juice is an anti bacterial and a good germicidal solution which helps in removing the unseen bacteria on our hands.

They are. solids liquids gases and plasma. and fift one in man made.

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:

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:

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)

Answer:

water wave shake energy over the surface to the sea, while sound waves thump energy trough the body of the air. sound waves are compression waves

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Answer:

working with intense pressure and heat

Explanation: you would you have to work with intense pressure and heat in order to fuse two hydrogen nuclei together to create helium isotopes.  

Answer:

The main problem is achieving ignition to start the reactions. Fusion reactions can occur only at extremely high temperatures.

Explanation:

Answer:A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Such fact-supported theories are not "guesses" but reliable accounts of the real world.

Should be right

A scientific theory is defined to be the part and explanation of the natural world, its phenomena, and the detailed description of the working. Thus, option D is correct.

A scientific theory is said to be the well-accepted and well-proposed explanation of the topic matter that has repeatedly undergone experiments to prove its ingenuity and uses well-constructed facts and hypotheses.

The hypothesis is the basis of the scientific theory as it gives the idea about the subject issue for which the experimental design is set for the analysis and reach a conclusion.

The scientific theory is proposed based on a hypothesis that assumes something based on limited evidence that is evaluated and undergoes experiments for it to be proved true or false.

Therefore, option D. a scientific theory is the explanation of the working of the natural world.

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Answer:

the answer is C

Explanation:

Record the time to complete a chemical reaction

The step that will be part of a lab procedure is; "Record the time to complete a chemical reaction."

A lab procedure refers to something that is done in the laboratory as part of an experiment.

If we look at the options carefully, we will notice that the only thing that is part of a laboratory experiment is "Record the time to complete a chemical reaction."

This action can be carried out in a live lab procedure.

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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:

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:

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: B. Stay the same

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 .

Can youmark my answers the brainliest.

Answer:

Some errors includes:

- Having contradictory information

- Exaggerated and false cliams

- Reliance on bias rather than facts

- etc

Explanation:

Pseudoscience is a non-science that falsely portrays itself as real science. It does so by copying parts of real science or ignoring sections of the scientific method within an investigation. Even a tiny mistake can turn a scientific explanation into a pseudoscientific claim.

For example, if a group of scientists want to know if students prefer the taste of a particular type of soda, they must control all factors in their experiment except for the students' sense of taste. If they conduct their tests on students and allow them to see the color of the soda they are testing, then their results are unreliable. There is bias in their results. They would not be able to claim any preference for one soda or another because students may have picked a soda based on its color, not its taste.

Given :

Mass of helium sample , [tex]m=1.73\times 10^{-3}\ g[/tex] .

Density of helium , [tex]\rho=0.178\times 10^{-3} \ g/cm^3[/tex] .

To Find :

The volume in millilitres .

Solution :

Density is given by , [tex]\rho=\dfrac{m}{V}[/tex]

So , volume is , [tex]V=\dfrac{m}{\rho}[/tex]

Putting given values in above equation we get :

[tex]V=\dfrac{1.73\times 10^{-3}}{0.178\times 10^{-3}}\ ml\\\\V=9.72\ ml[/tex]

Therefore , volume of sample of helium is 9.72 ml .

Hence , this is the required solution .

The volume of sample in milliliters is 9.72 mL .

Given data:

The mass of sample is, [tex]m=1.73 \times 10^{-3} \;\rm g[/tex].

The density of the helium sample is, [tex]\rho = 0.17847 \;\rm g/L =0.17847 \times 10^{-3} \;\rm g/cm^{3}[/tex].

The given problem is based on the concept of density. The density of any substance is equal to the mass per unit volume of the substance. The expression is given as,

[tex]\rho =\dfrac{m}{V}\\\\\\V =\dfrac{m}{\rho}\\\\\\V =\dfrac{1.73 \times 10^{-3}}{0.17847 \times 10^{-3}}\\\\V =9.72 \;\rm mL[/tex]

Thus, we can conclude that the volume of sample in milliliters is 9.72 mL .

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Answer:

There is spoilage microbes growing on the food, such as bacteria, yeasts, and mold. The odor can either come from the chemicals that are released from the food as the microbes decompose it down, or the chemicals are produced by the microbes themselves.

Answer:

When food goes bad and starts to become pungent, it is most often due to the growth of spoilage microbes such as bacteria, yeasts and mold. Odors can come from two sources: chemicals that are released from the food as the microbes decompose it, or chemicals produced directly by the microbes themselves.

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Answer:

THE VOLUME OF 0.200M CALCIUM HYDROXIDE NEEDED TO NEUTRALIZE 35 mL of 0.050 M NITRIC ACID IS 43.75 mL.

Explanation:

Using

Ca VA / Cb Vb = Na / Nb

Ca = 0.0500 M

Va = 35 mL

Cb = 0.0200 M

Vb = unknown

Na = 2

Nb = 1

Equation for the reaction:

Ca(OH)2 + 2HNO3 --------> Ca(NO3)2 + 2H2O

So therefore, we make Vb the subject of the equation and solve for it

Vb = Ca Va Nb / Cb Na

Vb = 0.0500 * 35 * 1 / 0.0200 * 2

Vb = 1.75 / 0.04

Vb = 43.75 mL

The volume of 0.02M calcium hydroxide required to neutralize 35 mL of 0.05 M nitric acid is 43.75 mL

The volume of 0.0200 M calcium hydroxide that would be required to neutralize 35.00 mL of 0.0500 M nitric acid will be 43.75 mL

From the equation of the reaction:

[tex]Ca(OH)_2 + 2 HNO_3 ---> Ca(NO_3)_2 + 2 H_2O[/tex]

The mole ratio of calcium hydroxide to nitric acid is 1:2.

Mole of nitric acid = molarity x volume

                             = 0.0500 x 35.00/1000

                              = 0.00175

Thus, the mole of the calcium hydroxide can be calculated as:

                       0.00175/2 = 0.000875

Volume of calcium hydroxide = mole/molarity

                                 = 0.000875/0.0200

                                  = 0.04375 L

                                  = 43.75 mL

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Answer: properties

Explanation:

The element which has the properties

Mallablity

Ductility

Lusterous

High electric. Conductivity

High tensile strength is said to be metal.