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Ksju [112]
3 years ago
13

For years, surgeons have had great success using _____.

Chemistry
2 answers:
sweet-ann [11.9K]3 years ago
7 0
C artificial heart valves
FrozenT [24]3 years ago
6 0
C the artifical heart
You might be interested in
What volume of nitrogen dioxide is formed at 735 torr and 28.2 °C by reacting 3.56 cm3 of copper (d = 8.95 g/cm3) with 200 mL of
weqwewe [10]

Answer:

25.76 L

Explanation:

Given, Volume of Copper = 3.56 cm³

Density = 8.95 g/cm³

Considering the expression for density as:

Density=\frac {Mass}{Volume}

So,

So, Mass= Density * Volume = 8.95 g/cm³ * 3.56 cm³ = 31.862 g

Mass of copper = 31.862 g

Molar mass of copper = 63.546 g/mol

The formula for the calculation of moles is shown below:

moles = \frac{Mass\ taken}{Molar\ mass}

Thus,

Moles= \frac{31.862\ g}{63.546\ g/mol}

<u>Moles of copper = 0.5014 moles </u>

Given, Volume of nitric acid solution = 200 mL = 200 cm³

Density = 1.42 g/cm³

Considering the expression for density as:

Density=\frac {Mass}{Volume}

So,

So, Mass= Density * Volume = 1.42 g/cm³ * 200 cm³ = 284 g

Also, Nitric acid is 68.0 % by mass. So,  

Mass of nitric acid = \frac {68}{100}\times 284\ g = 193.12 g

Molar mass of nitric acid = 63.01 g/mol

The formula for the calculation of moles is shown below:

moles = \frac{Mass\ taken}{Molar\ mass}

Thus,

Moles= \frac{193.12\ g}{63.01\ g/mol}

<u>Moles of nitric acid = 3.0649 moles </u>

According to the reaction,  

Cu_{(s)}+4HNO_3_{(aq)}\rightarrow Cu(NO_3)_2_{(aq)} + 2NO_2_{(g)} + 2H_2O_{(l)}

1 mole of copper react with 4 moles of nitric acid

Thus,  

0.5014 moles of copper react with 4*0.5014 moles of nitric acid

Moles of nitric acid required = 2.0056 moles

Available moles of nitric acid = 3.0649 moles

<u>Limiting reagent is the one which is present in small amount. Thus, nitric acid is present in large amount, copper is the limiting reagent. </u>

The formation of the product is governed by the limiting reagent. So,

1 mole of copper on reaction forms 2 moles of nitrogen dioxide

So,

0.5014 mole of copper on reaction forms 2*0.5014 moles of nitrogen dioxide

<u>Moles of nitrogen dioxide = 1.0028 moles </u>

Given:  

Pressure = 735 torr

The conversion of P(torr) to P(atm) is shown below:

P(torr)=\frac {1}{760}\times P(atm)

So,  

Pressure = 735 / 760 atm = 0.9632 atm

Temperature = 28.2 °C

The conversion of T( °C) to T(K) is shown below:

T(K) = T( °C) + 273.15  

So,  

T₁ = (28.2 + 273.15) K = 301.35 K  

Using ideal gas equation as:

PV=nRT

where,  

P is the pressure

V is the volume

n is the number of moles

T is the temperature  

R is Gas constant having value = 0.0821 L.atm/K.mol

Applying the equation as:

0.9632 atm × V = 1.0028 mol × 0.0821 L.atm/K.mol × 301.35 K  

<u>⇒V = 25.76 L</u>

4 0
3 years ago
What is the function of a mordant in gram staining?
Anna71 [15]
The  function  of  mordant  in  the   gram  staining  is  to   expose  grams  positive  cell  to  the  decolorizer  which  dissolves  the  lipids  in  the  cell  wall   thus  allowing  the  crystals  violent-iodine  to  leach  out  of  the  cell. This  facilitate  the  cell  subsequently   be  stained  by  with  safranin.
5 0
3 years ago
Read 2 more answers
Determine the missing species:
Galina-37 [17]

Answer: 4. ^{0}_{-1}\textrm{e} and ^{0}_{1}\textrm{e}

Explanation:

a) The given reaction is ^{41}_{20}\textrm{Ca}+^{x}_{y}\textrm{X}\rightarrow ^{41}_{19}\textrm {K}

As the mass on both reactant and product side must be equal:

41+x=41

x=0

As the atomic number on both reactant and product side must be equal:

20+y=19

y=-1

^{41}_{20}\textrm{Ca}+^{0}_{-1}\textrm{e}\rightarrow ^{41}_{19}\textrm {K}

b) ^{15}_{8}\textrm{O}\rightarrow ^{15}_{7}\textrm{N}+^{x}_{y}\textrm{X}

Total mass on reactant side = total mass on product side

15 =15 + x

x = 0

Total atomic number on reactant side = total atomic number on product side

8 = 7 + y

y = 1

^{15}_{8}\textrm{O}\rightarrow ^{15}_{7}\textrm{N}+^{0}_{1}\textrm{e}

5 0
3 years ago
Nitric oxide (NO) is a gaseous molecule with lipid solu- bility similar to that of O2 and CO2. Endothelial cells lining arteries
svp [43]

Answer:

NO passively diffuses down its concentration gradient through the endothelial cell plasma membrane out of the cell and then passiveley diffuses through the plasma membrane into the cytoplasm of the smooth muscle cell, where it acts to decrease contraction.

Explanation:

Hello,

At first, we must consider that O_2 and CO_2, NO passively diffuses through membranes. As it is produced by an enzyme and accumulates in the endothelial cell cytosol, NO passively diffuses down its concentration gradient through the endothelial cell plasma membrane out of the cell and then passiveley diffuses through the plasma membrane into the cytoplasm of the smooth muscle cell, where it acts to decrease contraction.

Best regards

5 0
4 years ago
How was or wasn't the scientific method followed in this experment
Andreas93 [3]

Answer:

The best answer would be:

C. The scientific method was followed because the experiment tested the hypothesis and produced reliable results.

Explanation:

The purpose of an experiment is to test the hypothesis. It is true that having an experimental group and a control group was following the scientific method but the data gathering and documentation was also part of the scientific method. So the best answer would be C.

Writing the question is not necessary. It is merely part of forming a hypothesis. The scientific method does not require many scientists to perform the experiment, but it does require that the experiment be repeatable, so it can be tested again.

3 0
4 years ago
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