Can cells have different types of openings?

When magnesium reacts with sulfuric acid the products are magnesium sulfate and hydrogen. If there are 15 grams of magnesium at

Sergeeva-Olga [200]

Answer: 15 grams of magnesium will be present in the magnesium sulfate

Explanation:

According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side.

The balanced chemical reaction is:

$Mg+H_2SO_4\rightarrow MgSO_4+H_2$

As the mass remains conserved at the end of the reaction, there will be 15 grams of Magnesium in magnesium sulphate.

8 0

3 years ago

Calculate the equilibrium constant for the reaction: 2 Cr + 3 Pb2+ ----> 3 Pb + 2 Cr3+ at 25oC. Eocell = 0.61 V

sattari [20]

Answer:

The value is $K = 8*10^{61}$

Explanation:

From the question we are told that

The equation is $2 Cr + 3Pb^{2+} \to 3Pb + 2Cr^{3+}$

The temperature is $T = 25^oC = 298 K [room \ temperature ]$

The emf at standard condition is $E^o_{cell} = 0.61 \ V$

Generally at the cathode

$3Pb^{2+}(aq) + 6 e- --> 3Pb(s)$

At the anode

$2Cr^{3+} + 6e^- \to 2Cr$

Generally for an electrochemical reaction, at room temperature the Gibbs free energy is mathematically represented as

$G = n* F * E^o_{cell}$

Here n is the no of electron with value n = 6

F is the Faraday's constant with value 96487 J/V

=> $G = 6 * 96487 * 0.61$

=> $G = 3.5 *10^{5} \ J$

This Gibbs free energy can also be represented mathematically as

$G = RTlogK$

Here R is the cell constant with value 8.314J/K

K is the equilibrium constant

From above

=> $K = antilog^{\frac{G}{ RT} }$

Generally antilog = 2.718

=> $K = 2.718^{\frac{3.5 *10^5}{ 8.314* 298} }$

=> $K = 8*10^{61}$

6 0

3 years ago

In the reaction CuO(s) + CO2(g) → CuCO3(s), a. CO2 is the Lewis acid and CuCO3 is its conjugate base. b. O2– acts as a Lewis bas

adoni [48]

<u>Answer:</u> The correct answer is Option d.

<u>Explanation:</u>

According to Lewis acid-base concept:

The substance which is donating electron pair is considered as Lewis base and the substance which is accepting electron pair is considered as Lewis acid.

For the given chemical reaction:

$CuO(s)+CO_2(g)\rightarrow CuCO_3(s)$

$CO_2$ is accepting electron pair and is getting converted to $CO_3^{2-}$ . Thus, it is considered as Lewis acid.

$O^{2-}$ present in CuO is a Lewis base because it is donating electron pair.

Thus, the correct answer is Option d.

4 0

3 years ago

It is necessary to know the time of day and the position of the Sun or the stars relative to one's longitude line because ____.

allochka39001 [22]

Answer: the longitude line rotates with Earth, 360 degrees in 24 hours.

Explanation: In the old days, the position of the sun was used to tell which time of the day it is. But more modern findings, has shown that the longitude line matters too.

3 0

3 years ago

Water and minerals move up the xylem because of a vacuum created by _____.

Galina-37 [17]

Answer:

The right answer is B) evaporation

Explanation:

Transpiration occurs at the leaf surface which is the loss of water due to the evaporation. This phenomenon works as trigger of water and mineral movement above to the xylem. Due to the evaporation of water at the leaf, negative pressure is created at the surface of leaf. Tension is produced which results in the pull of water from roots up to the xylem vessels.

4 0

3 years ago