Blood samples for research or medical tests sometimes have heparin added. Why is this done? ​

Answers

Answer 1
It is essential for accurate results that the correct volume of blood is sampled to achieve a correct concentration (and dilution, if liquid heparin is used), and that blood and anticoagulant are well mixed immediately after sampling.

Related Questions

which of these is the smallest unit?
ds
ks
cs
ms

Answers

Answer:

ks

Explanation:

Is it right

Question 10 of 10 Which of the following compounds is the most stable? A. Agci B. LICI C. AlCl3 D. CuCl2​

Answers

Answer:

b

Explanation:


Which type of drug commonly marketed to consumers does not require a prescription?

A. antidepressant
B. blood pressure medication
C. pain reliever

Answers

C. pain reliever
ex. tylenol, aleve, etc.

Answer:

pain reliever

Explanation:

During a chemical reaction, how do the substances that form differ from the substances that react?

Answers

What the guy above me said

Perform the following calculation with the
correct number of significant figures.
12.62 +2.3 + 0.34 = ?

Answers

the answer is 15.26.

A 1.59 mol sample of Kr has a volume of 641 mL. How many moles of Kr are in a 4.41 L sample at the same temperature and pressure?

Answers

Answer:

The correct answer is 10.939 mol ≅ 10.94 mol

Explanation:

According to Avogadro's gases law, the number of moles of an ideal gas (n) at constant pressure and temperature, is directly proportional to the volume (V).

For the initial gas (1), we have:

n₁= 1.59 mol

V₁= 641 mL= 0.641 L

For the final gas (2), we have:

V₂: 4.41 L

The relation between 1 and 2 is given by:

n₁/V₁ = n₂/V₂

We calculate n₂ as follows:

n₂= (n₁/V₁) x V₂ = (1.59 mol/0.641 L) x 4.41 L = 10.939 mol ≅ 10.94 mol

The number of moles is 10.94 mol.

The calculation is as follows:

As per the Avogadro gases law, the no of moles at the same pressure & temperature should be proportional to the volume.

The following formula should be used:

[tex]n_1\div V_1 = n_2\div V_2\\\\n_2= (n_2\div V_1) \times V_2\\\\ = (1.59 mol\div 0.641 L) \times 4.41 L[/tex]

= 10.939 mol

= 10.94 mol

Therefore we can conclude that the number of moles is 10.94 mol.

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Which of the following biogeochemical cycles does not contain a molecule in a gaseous state?

Answers

The phosphorus cycle does not have a gaseous component. The inorganic form of phosphorus, phosphate, enters the soil from the weathering of rocks.

How might the molecules inside an ice pack be different from the liquid inside of an insulated cup?​

Answers

Answer:

The molecules inside the ice pack are frozen therefore they are stuck in place. The molecules inside an insulated cup aren't frozen but still stuck inside of their container so that they can not fly out.

Explanation:

Calculate the average atomic mass of an element containing 39.9% of atoms with a mass of 69 amu and 60.1% of atoms with a mass of 71 amu. Show your work for credit and round your answer to one decimal place.

Answers

Answer:

70.202 amu

Explanation:

From the question given above, the following data were obtained:

Isotope A:

Abundance (A%) = 39.9%

Mass of A = 69 amu

Isotope B:

Abundance (B%) = 60.1%

Mass of B = 71 amu

Average atomic mass =?

The average atomic mass of the element can be obtained as follow:

Average atomic mass = [(Mass of A × A%)/100] + (Mass of B × B%)/100]

= [(69 × 39.9)/100] + [(71 × 60.1)/100]

= 27.531 + 42.671

= 70.202 amu

Therefore, the average atomic mass of the element is 70.202 amu

What is the formula for Mercury (I) Bisulfate?​

Answers

Answer:

Work shown below!

Explanation:

[tex]Hg^{+1} HSO_{4} =HgHSO_{4}[/tex]

What is the correct formula that would result from the combination
of the two ionic species?

Answers

The correct formula : BeSO₄

Further explanation

Chemical formula shows the composition number of the constituent atoms

Polyatomic ion consists of 2 or more ions

The equal charge of the two ions will cancel each other out, while the different charges of the two ions will be crossed each other

Be²⁺ (monatomic ion) has a positive charge of +2, while SO₄²⁻ (polyatomic ion) has a negative -2 charge, so that the two charges with the same magnitude but with different charges cancel each other out so that the compound form is BeSO4

At constant pressure for which of the reactions shown below should Delta H be greater than Delta E°?
1.2 SO2(g) + O2(g) - 2 SO3(g)
II. C5H12(9) + 8 O2(g) - 5 CO2(g) + 6 H20(1)
III. H2(g) + Br2(g) → 2 HBr(9),
IV. N204(9) - 2 NO2(g)

Answers

Answer: [tex]N_2O_4(g)\rightarrow 2NO_2(g)[/tex] has higher value of [tex]\Delta H[/tex] than [tex]\Delta E[/tex]

Explanation:

The realtion between enthalpy change and internal energy change is:

[tex]\Delta H=\Delta E+\Delta n_gRT[/tex]

where,

=  enthalpy of the reaction

= internal energy of the reaction

[tex]\Delta n_g[/tex] = change in the gaseous moles of the reaction = Moles of product - Moles of reactant

R = gas constant

T = temperature

1. [tex]2SO_2(g)+O_2(g)\rightarrow 2SO_3(g)[/tex]

[tex]\Delta n_g[/tex] = 2-3 = -1

2. [tex]C_5H_{12}(g)+8O_2(g)\rightarrow 5CO_2(g)+6H_2O(l)[/tex]

[tex]\Delta n_g[/tex] = 5-9 = -4

3. [tex]H_2(g)+Br_2(g)\rightarrow 2HBr(g)[/tex]

[tex]\Delta n_g[/tex] = 2-2 = 0

4. [tex]N_2O_4(g)\rightarrow 2NO_2(g)[/tex]

[tex]\Delta n_g[/tex] = 2-1 = 1

Thus reaction . [tex]N_2O_4(g)\rightarrow 2NO_2(g)[/tex] has higher value of [tex]\Delta H[/tex] than [tex]\Delta E[/tex]

At constant pressure the given reaction that shows ΔH would be greater than ΔE is;

IV); N₂0₄(g) 2NO₂(g)

In chemistry, he meaning of ΔH and ΔE are;

- ΔH means the change in enthalpy, which is heat content.

- ΔE means the change in energy of a system.

Now, for a closed system the relationship between ΔH and ΔE is given by;

ΔH = ΔE + PΔV

where PΔV = ΔnRT

Thus; ΔH = ΔE + ΔnRT

where Δn = number of moles of product in the gaseous state - number of moles of reactants.

Thus, if Δn is negative, then ΔE would be greater than ΔH but if Δn is positive, then ΔH would be greater than ΔE

I) 2SO₂(g) + O₂(g) ⇒ 2SO₃(g)

number of moles of product = 2

number of moles of reactants = 2 + 1 = 3

Δn = 2 - 3

Δn = -1 and so ΔE would be greater than ΔH

II) C₅H₁₂(g) + 8O₂(g) ⇒ 5CO₂(g) + 6H₂0(l)

number of moles of product = 5 (6 is not used because water is in liquid and not gas)

number of moles of reactants = 8 + 1 = 9

Δn = 5 - 9

Δn = -4 and so ΔE would be greater than ΔH

III) H₂(g) + Br₂(g) → 2HBr(g)

number of moles of product = 2

number of moles of reactants = 1 + 1 = 2

Δn = 2 - 2

Δn = 0 and so ΔE would be equal to ΔH

IV) N₂0₄(g) → 2NO₂(g)

number of moles of product = 2

number of moles of reactants = 1

Δn = 2 - 1

Δn = +1 and so ΔH would be greater than ΔE

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Write the complete and balanced combustion reaction for H2+O2—>

Answers

Answer:

2H2 + 02 --> 2H20

Explanation:

H2 + 02 --> H2O

H =2x2 = 4                |   H = 2 x 2 = 4

                                 |

O =2                          |   O = 1 x 2 = 2

dm me if u have questions regarding the solution hihi :)

Two gas jars are connected to each other, but they are separated by a closed valve. One gas jar contains oxygen, and the other is empty. What will happen when the valve is opened? (3 points)

a
Oxygen molecules will remain in their original jar because of the very high density of the oxygen molecules.

b
Oxygen molecules will remain in their original jar because there is enough space in the original jar.

c
Oxygen molecules will spread evenly throughout both jars because of weak intermolecular forces.

d
Oxygen molecules will spread through both jars because of the high molecular weight of oxygen.

Answers

Answer:

d) Oxygen molecules will spread through both jars because of the high molecular weight of oxygen.

Explanation:

Oxygen molecules will spread evenly throughout both jars because of weak intermolecular forces.

Intermolecular forces hold the molecules of matter together in a particular state of matter.

Gases have the weakest intermolecular forces between them. As such, the molecules of gases are isolated from each other and they move at very high velocities.

Due to weak intermolecular forces between the molecules of oxygen gas, when the valve between the two jars is opened, oxygen gas spreads evenly throughout the both jars.

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What is the percent yield for carbon dioxide if 10.0 grams of carbon
monoxide yielded 12.81 grams of carbon dioxide from the reaction
below?
2 CO + O2 → 2 CO2

Answers

The percent yield : 81.5%

Further explanation

Percent yield is the compare of the amount of product obtained from a reaction with the amount you calculated

General formula:

Percent yield = (Actual yield / theoretical yield )x 100%

An actual yield is the amount of product actually produced by the reaction. A theoretical yield is the amount of product that you calculate from the reaction equation according to the product and reactant coefficients

Reaction

2CO+O₂⇒2CO₂

mol CO(MW=28,01 g/mol)

[tex]\tt \dfrac{10}{28.01}=0.357[/tex]

mass CO₂ (theoretical)(MW=44,01 g/mol)

[tex]\tt 0.357\times 44.01=15.712~g[/tex]

the percent yield :

[tex]\tt \dfrac{12.81}{15.712}\times 100\%=81.5\%[/tex]

CAN you pleaaaase solve this? please please please

Answers

Answer:

115.2ml of water should be added.

Explanation:

We start with 46.2ml of 1.396M sugar solution;

We want to end up with a 0.56M sugar solution;

Finding the number of moles in the sugar solution to begin with:

moles of sugar in solution initially = 46.2 × 1.396 = 64.4952

Vd = volume of desired solution (i.e. 0.56M solution)

w = volume of water added

Vd = (46.2 + w)

Using the mol = vol' × conc'n equation:

64.4952 = Vd × 0.56

Vd = 64.4952/0.56

Vd = 115.17

46.2 + w = 115.17

w = 115.17 - 46.2

w = 68.97ml

The pH of 0.259 M solution of an unknown acid is measured to be 2.353. What is the Ka of the acid?

Answers

Answer:

[tex]Ka=7.73x10^{-5}[/tex]

Explanation:

Hello!

In this case, since the pH is measure of the amount of hydrogen ions in solution, first given the pH we can compute the concentration of hydrogen ions via:

[tex]pH=-log([H^+])[/tex]

[tex][H^+]=10^{-pH}=10^{-2.353}=4.436x10^{-3}M[/tex]

Thus, since the ionization of the given acid, leads to the following equilibrium expression as it is a weak one:

[tex]Ka=\frac{[H^+][A^-]}{[HA]}[/tex]

We notice the concentration of hydrogen ions equal the concentration of the acids conjugate base, so we can compute:

[tex]Ka=\frac{4.436x10^{-3}*4.436x10^{-3}}{0.259-4.436x10^{-3}}\\\\Ka=7.73x10^{-5}[/tex]

Best regards!

What is the frequency of a photon that has a wavelength of 754 um? ​

Answers

Answer:

Explanation:

What is the frequency of a photon that has a wavelength of 754 um? ​

A falling book in mid-air has___
A. both potential and kinetic energy
B. only kinetic energy
C. chemical energy
D. only potential energy​

Answers

The potential and kinetic energy of a falling book is present. Kinetic energy is indeed the force driving motion, manifested in the motion of a particle, an object, or a collection of particles.

The correct answer is A

Where is the lack of kinetic energy located?

Kinetic energy is the term for the energy present in an object in motion. Examples of velocity include your movement as you walk down the street and the planet's rotation around the sun. The formula for kinetic energy is as follows: K.E. is equal to half of an object's mass times its square velocity, or m/v2.

How come kinetic energy is so crucial?

The capacity of kinetic energy to perform work is perhaps its most significant quality. The force applied to that of an object when it is moving is referred to as work. This intimate relationship between work and energy makes them go together.

To know more about  kinetic energy visit:

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if one knows the mass and the molar mass of product D in a chemical reaction, one can determine the mass of product D procued by using the?

Answers

Answer:

Number of moles

Explanation:

Using the number of moles in chemical reactions, we can determine the quantity of products and even the reactants that are combining to form them.

The number of moles is derived using the expression below is;

     Number of moles  = [tex]\frac{mass}{molar mass}[/tex]

Once we establish the number of moles of any of the specie given from the mass and molar mass, we can relate it to any other species.

Introduction:
Briefly describe the physical behavior you investigated.
What is the exploration about?
What are you trying to discover?
Relate to any previous work.
Use new vocabulary words, if you can.

Answers

Answer: im not sure if this is the best answer but i wrote, "This exploration is about how the volume of a gas varies with temperature, and what the effect does to the gas and what effect it has on the results."

Explanation: hope this helps.

This exploration is about how the volume of a gas varies with temperature, and what the effect does to the gas and what effect it has on the results."

Thus, For persons with autism, life can be incredibly stressful at times, and their behaviour may be an indication of their utter exasperation or suffering in reaction to a variety of pressures.

Some people struggle with the idea of time and sequencing, thus this can involve onerous tasks, meeting new people, experiencing unpleasant sensory stimuli, a change in routine, switching activities, or having to wait for anything.

The individual may have realized how effective their actions could be in influencing their environment. A behaviour that was initially a reaction to physical discomfort or frustration may later develop into a strategy for evading a request or getting rid of an uncomfortable circumstance.

Thus, This exploration is about how the volume of a gas varies with temperature, and what the effect does to the gas and what effect it has on the results."

Learn more about Temperature, refer to the link:

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The question is Incomplete, the complete question is:

Briefly describe the physical behavior?

What is the exploration about?

What are you trying to discover?

Relate to any previous work.

Use new vocabulary words, if you can.

In the exploration, I was a bird trying to eat bugs placed in different backgrounds. Each bug was adifferent color, and the color either matched or stood out against the background. What I wastrying to discover was how creatures adapted to their environment and if blending in with theirenvironment helped them or hindered them. I discovered that yes, blending in with theenvironment helps creatures survive.

Scientists study and record seismic data and volcanic activity in order to support: Convection in the Lithosphere Theory of Plate Tectonics Sea Floor Spreading Theory of Continental Drift

Answers

Answer:

Theory of Plate Tectonics

Explanation:

Scientists especially Geologists study and record seismic data and volcanic activities in order to support the theory of plate tectonics.

The theory of plate tectonics suggests that the earth is broken into slabs called the lithosphere that moves over the fluid asthenosphere below.

The use of seismic data presents scientists with a way of vertically looking deep into the earth. Volcanic activities also presents us with the kind of materials down within the earth. Also, coupled with this data, scientists use GPS sensors to monitor the rate of movement of the earth. When studying plate tectonics, it invariably culminates in the study of sea floor spreading and theory of continental drift.

Consider the following reaction. MgCl2(aq)+2NaOH(aq)⟶Mg(OH)2(s)+2NaCl(aq) A 187.0 mL solution of 0.103 M MgCl2 reacts with a 33.58 mL solution of 0.839 M NaOH to produce Mg(OH)2 and NaCl. Identify the limiting reactant.

Answers

Answer:

NaOH is the limiting reactant and MgCl2 is in excess.

Explanation:

let's calculate the mole of each reactant.

number of moles of MgCl2 = [tex]\frac{187}{1000} L* 0.103 mol / L =0.01926 mol\\[/tex]

number of moles of NaOH = [tex]\frac{33.58 }{1000}L * 0.839 mol/L =0.0282 mol[/tex]

as per the reaction , 1 mol of Magnesium choloride reacts with 2 moles of NaOH

hence 0.01926 needs 0.01926x2= 0.03852 moles of NaOH , but there are only 0.0282 moles of NaOH available .

The limiting reactant for the reaction between 187.0 mL solution of 0.103 M MgCl₂ and 33.58 mL solution of 0.839 M NaOH is NaOH

We'll begin by calculating the number of mole of MgCl₂ and NaOH present in the solution.

For MgCl₂:

Volume = 187 mL = 187 / 1000 = 0.187 L

Molarity = 0.103 M

Mole of MgCl₂ =?

Mole = Molarity x Volume

Mole of MgCl₂ = 0.103 × 0.187

Mole of MgCl₂ = 0.019 mole

For NaOH:

Volume = 33.58 mL = 33.58 / 1000 = 0.03358 L

Molarity = 0.839 M

Mole of NaOH =?

Mole = Molarity x Volume

Mole of NaOH = 0.839 × 0.03358

Mole of NaOH = 0.028 mole

Finally, we shall determine the limiting reactant. This can be obtained as follow:

MgCl₂ + 2NaOH —> Mg(OH)₂ + 2NaCl

From the balanced equation above,

2 moles of NaOH required 1 mole of MgCl₂.

Therefore, 0.028 mole of NaOH will require = [tex]\frac{0.0282}{2}\\[/tex] = 0.014 mole of MgCl₂

From the calculations made above, we can see that only 0.014 mole of MgCl₂ out of 0.019 mole reacted completely with 0.028 mole of NaOH.

Therefore, NaOH is the limiting reactant and MgCl₂ is the excess reactant.

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Which additional product balances the reaction H2SO4 + 2NaOH → Na2SO4 + ? 2H2O 2OH H2O2 H3O

Answers

Answer:

a) 2H2O

Explanation:

I took the quiz

Answer:

2H20 or A- the other person was right:) give them brainliest.

Explanation:

I just took the test.

why is a bannana curved?

Answers

Answer:

Explanation:

It's because of the sun! Bananas are curved so they can retrieve sunlight.

give him the brainliest

Models can represent systems
and processes.this is a true or false question

Answers

Answer:

True

Explanation:

Hope this helps! :)

Answer:

This is True.

Explanation:

What type of reaction is: 4 Fe + 3 O2 → 2 Fe2O3
A. synthesis
B. double replacement
C. decomposition
D. single replacement

Answers

Answer:

A. synthesis

Explanation:

The reaction given is a synthesis reaction in which two substances combines to give a product.

In this reaction:

      4Fe + 3O₂ →  2Fe₂O₃

The reaction involves the formation of a single product from two or more reactants.

The formation of a compound from union of the constituent elements also falls into this category of reaction.

A nuclear equation is balanced when? ​

Answers

A balanced nuclear reaction equation indicates that there is a rearrangement during a nuclear reaction, but of subatomic particles rather than atoms. Nuclear reactions also follow conservation laws, and they are balanced in two ways: The sum of the mass numbers of the reactants equals the sum of the mass numbers of the products.

Please mark brainliest:)

In which of the following elements is the least
amount of energy required to remove the most
loosely bound electron from an atom in the gaseous
state?
A) Sr
B) Ar
C) Al
D C

Answers

Answer:

A) Sr

Explanation:

Strontium will require the least amount of energy to remove the most loosely bound electrons from its atom in gaseous state.

This parameter is known as the ionization energy. It is defined as the readiness of an atom to lose an electron.

Metals in group 1 and 2 generally have very low ionization energy due to their large electropositivity The more electropositive a metal is, the lower its ionization energy. This is the reason why strontium will have the least ionization energy.

18 protons
22 neutrons
18 electrons
how do i draw this ? please help ASAP.

Answers

Explanation:

You need to remember a few things if you want the answer to this question...

A atom has a circle within a circle so consider that it looks like a double circle..Protons and neutrons go in the center of that double circle..Electrons go on the outer sides of the two circles.Because of the given numbers of protons, neutrons, and electrons we know that the element you need to draw is Argon.

Therefore you need to draw a atom that is similar to this:

Hope this helps.

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