Which substance is liquid at 0°C? 1. alcohol 2. aluminum 3. ammonia 4. copper

What is the surface composition of planets in the solar system?

Stels [109]

Answer:

A: Helium or Hydrogen

Explanation:

Terrestrial planets are the 4 inner most planets of the solar system which are mercury, venus, earth, Mars, while the giant planets are the 4 outer most which are Jupiter, Saturn, Uranus and Neptune.

Now, these outer most ones are the surface ones and are surrounded primarily by layers of hydrogen and helium gases.

3 0

3 years ago

Which experimental feature of the MALDI-MS technique allows the separation of ions formed after the adduction of tissue molecule

34kurt

Answer:

The experimental feature of the MALDI-MS technique which allows the separation of ions formed after the adduction of tissue molecules:

B) Velocity of ions depends on the ion mass-to-charge ratio.

Explanation:

The option a is not correct as distance traveled by ions doesn't depend upon the ion charge rather it depends upon time for which you leave the sample to run.
The option b is correct as velocity of ions depends on the ion mass-to-charge ratio because separation is done due to mass to charge ratio feature.
The option c is incorrect as time of travel is not inversely proportional to the ion-to-mass ratio because the ion will move across the gel until you stop the electric field.
The option d is not correct as electric field between MALDI plate and MS analyzer is though uniform but this feature doesn't allow the separation of ions.

6 0

3 years ago

Which of the following elements is going to be the most reactive and why? Nitrogen or Oxygen?

bagirrra123 [75]

Answer:

(C) Oxygen because it has the strongest attractive force and the largest

electronegativity

Explanation:

Oxygen will be most reactive

configuration = $1s^22s^22p^4$

As oxygen need only two electrons to complete its octet.

Oxygen will have stronger force than nitrogen as it will tend to pull electrons more to complete its octet. Also along the period electronegativity increases so oxygen has higher electronegativity than nitrogen

7 0

3 years ago

A solution contains 0.0440 M Ca2 and 0.0940 M Ag. If solid Na3PO4 is added to this mixture, which of the phosphate species would

Olenka [21]

Answer:

C. $Ca_3(PO_4)_2$ will precipitate out first

the percentage of $Ca^{2+}$ remaining = 12.86%

Explanation:

Given that:

A solution contains:

$[Ca^{2+}] = 0.0440 \ M$

$[Ag^+] = 0.0940 \ M$

From the list of options , Let find the dissociation of $Ag_3PO_4$

$Ag_3PO_4 \to Ag^{3+} + PO_4^{3-}$

where;

Solubility product constant Ksp of $Ag_3PO_4$ is $8.89 \times 10^{-17}$

Thus;

$Ksp = [Ag^+]^3[PO_4^{3-}]$

replacing the known values in order to determine the unknown ; we have :

$8.89 \times 10 ^{-17} = (0.0940)^3[PO_4^{3-}]$

$\dfrac{8.89 \times 10 ^{-17}}{(0.0940)^3} = [PO_4^{3-}]$

$[PO_4^{3-}] =\dfrac{8.89 \times 10 ^{-17}}{(0.0940)^3}$

$[PO_4^{3-}] =1.07 \times 10^{-13}$

The dissociation of $Ca_3(PO_4)_2$

The solubility product constant of $Ca_3(PO_4)_2$ is $2.07 \times 10^{-32}$

The dissociation of $Ca_3(PO_4)_2$ is :

$Ca_3(PO_4)_2 \to 3Ca^{2+} + 2 PO_{4}^{3-}$

Thus;

$Ksp = [Ca^{2+}]^3 [PO_4^{3-}]^2$

$2.07 \times 10^{-33} = (0.0440)^3 [PO_4^{3-}]^2$

$\dfrac{2.07 \times 10^{-33} }{(0.0440)^3}= [PO_4^{3-}]^2$

$[PO_4^{3-}]^2 = \dfrac{2.07 \times 10^{-33} }{(0.0440)^3}$

$[PO_4^{3-}]^2 = 2.43 \times 10^{-29}$

$[PO_4^{3-}] = \sqrt{2.43 \times 10^{-29}$

$[PO_4^{3-}] =4.93 \times 10^{-15}$

Thus; the phosphate anion needed for precipitation is smaller i.e $4.93 \times 10^{-15}$ in $Ca_3(PO_4)_2$ than in $Ag_3PO_4$ $1.07 \times 10^{-13}$

Therefore:

$Ca_3(PO_4)_2$ will precipitate out first

To determine the concentration of $[Ca^+]$ when the second cation starts to precipitate ; we have :

$Ksp = [Ca^{2+}]^3 [PO_4^{3-}]^2$

$2.07 \times 10^{-33} = [Ca^{2+}]^3 (1.07 \times 10^{-13})^2$

$[Ca^{2+}]^3 = \dfrac{2.07 \times 10^{-33} }{(1.07 \times 10^{-13})^2}$

$[Ca^{2+}]^3 =1.808 \times 10^{-7}$

$[Ca^{2+}] =\sqrt[3]{1.808 \times 10^{-7}}$

$[Ca^{2+}] =0.00566$

This implies that when the second cation starts to precipitate ; the concentration of $[Ca^{2+}]$ in the solution is 0.00566

Therefore;

the percentage of $Ca^{2+}$ remaining = concentration remaining/initial concentration × 100%

the percentage of $Ca^{2+}$ remaining = 0.00566/0.0440 × 100%

the percentage of $Ca^{2+}$ remaining = 0.1286 × 100%

the percentage of $Ca^{2+}$ remaining = 12.86%

5 0

3 years ago

Give 3 examples of conduction, radiation, and convection.

cupoosta [38]

Answer:Conduction: Touching a stove and being burned. Ice cooling down your hand

Convection: Hot air rising, cooling, and falling (convection currents)

Radiation: Heat from the sun warming your face

Explanation:

3 0

3 years ago

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