An atom with 25 protons and 27 electrons has a charge of + True False??

According to nature of flow, convective heat transfer is classified into natural convection

Brrunno [24]

Answer:

When the motion of the fluid results due to natural means like the buoyancy effect, that is, the elevation of the warmer fluid and the fall of the cooling fluid is termed as natural convection. Boiling water is the everyday illustration of the natural convection, in the process, the passing of the heat takes place from the burner into the pot, and heats the water present at the bottom.

On the other hand, when the fluid is forced to flow in a tube or over the surface by external means like with the help of a fan or a pump is termed as forced convection. The use of a fan on a hot summer day is an everyday illustration of forced convection. An example of effective heat transfer is the sweat produced by our body. Therefore, when one switches off the fan, the air present around the body captivates the water vapor until it gets saturated. It takes place for some time and stops eventually, which makes one feel hotter.

At that time, when the fan is switched back again, the air surrounding the body starts to move again, without completely getting saturated, and thus, evaporation of the sweat takes place that also contains the heat of the body and one feels cooler.

6 0

3 years ago

6. Under standard-state conditions, what spontaneous reaction will occur in aqueous solution among the ions Ce4+, Ce3+, Fe3+, an

xz_007 [3.2K]

Answer:

ΔG° = -80.9 KJ

Assuming this reaction takes place at room temperature (25 °C):

K= $1.53x10^{14}$

Explanation:

1) Reduction potentials

First of all one should look up the reduction potentials for the species envolved:

$Ce^{4+} + e$ → $Ce^{3+}$ E°red=1.61V

$Fe^{3+} + e$ → $Fe^{2+}$ E°red=0.771V

2) Redox pair

Knowing their reduction pontentials one can determine a redox pair: one species must oxidate while the other is reducing. Remember: the table gives us the reduction potential, so if we want to know the oxidation potential all that has to be done is reverce the equation and change the potencial signal (multiply to -1).

1) $Ce^{4+}$ reduces while $Fe^{2+}$ oxidates

(oxidation) $Fe^{2+}$ → $Fe^{3+} + e$ E°oxi=-0.771V

(reduction) $Ce^{4+} + e$ → $Ce^{3+}$ E°red=1.61V

(overall equation) $Fe^{2+}+Ce^{4+}$ → $Ce^{3+}+Fe^{3+}$ E°=Ereduction + Eoxidation= 1.61 v+(-0.771 v) = 0.839v

The cell potential can also be calculated as the cathode potencial minus the anode potential:

E° = E cathode - E anode =1.61 v - 0.771 v=0.839 v

3) Gibbs free energy and Equilibrium constant

ΔG°=-nFE°, where 'n' is the number of electrons involved in the redox equation, in this case n is 1. 'F' is the Faraday constant, whtch is 96500 C. E° is the standard cell potencial.

ΔG°=-nFE°=-1*96500*0.839

ΔG° = - 80963 J = -80.9 KJ

The Nerst equation gives us the relation of chemical equilibrium and Electric potential.

E=E°- $\frac{RT}{nF} Ln Q$

Where 'R' is the molar gas constant (8.314 J/mol)

It's known that in the equilibrium E=0, so the Nerst equation, at equilibrium, becomes:

E°= $\frac{RT}{nF} Ln K$

Isolating for 'K' gives:

$K=e^{\frac{nFE^{o} }{RT} }$

This shows that 'K' is a fuction of temperature. Assuming this reaction takes place at room temperature (25 °C):

K= $1.53x10^{14}$

6 0

4 years ago

A test tube can be used to hold

Andrej [43]

What grade is this? I forgot but if u tell me the grade i can prob remember

5 0

3 years ago

URGENT!??! Please hurry ?!!!

Montano1993 [528]

Answer:

Table which was completed correctly is :

B) Answer choice G

Explanation:

Metals : Most of the elements in the periodic comes in the category of metal. They are found in left and middle of periodic table.

List of metals

Alkali : Li , Na , K ,Rb , Cs ,Fr

Alkaline : Be , Mg , Ca , Sr ,Ba ,Ra

Transition : Sc ,Ti ,V ,Cr ,Mn , Fe , Co, Ni Cu , Zn ,Y ,Zr ,Nb ,Mo ,Tc ,Ru , Rh , Pd , Ag , Cd , In , Sn, La ,Hf ,Ta ,W ,Re ,Os ,Ir ,Pt ,Au ,Hg

Non -Metals: Most of the p-block element are non metal. They are present in upper - right corner of the periodic table.

Non - metals : H , He , C ,N , O , F ,P ,S , Cl, Ar , Br , Xe ,At ,Rn,

Metalloid : They show properties of both the metals and the non - metals.

Also called as semimetals

Metalloid : B ,Si ,Ge ,As ,Sb ,Te ,Po

In table F :

B = metalloid , N = non metal ( wrong-match) , Ra = metal ( wrong-match) , He = Non - metal ( wrong-match)

In table G : Correctly matched

I = Non - metal , Ca = metal , Rb = metal , As = metalloid

In table H:

Ni = metal ( wrong-match) , C = metalloid ( wrong-match) , Mg = metal , Pb = Metal

In table J:

Cu = metal , Sb = Metalloid( wrong-match) , S = non metal( wrong-match) ,Ne = non metal

6 0

3 years ago

How many moles of carbon dioxide gas should be produced when 10.0 g of C2H6 are combusted at STP?

Finger [1]

Answer:

0.665 moles of CO₂

Explanation:

The balance chemical equation for the combustion of Ethane is as follow:

2 C₂H₆ + 7 O₂ → 4 CO₂ + 6 H₂O

Step 1: Calculate moles of C₂H₆ as;

Moles = Mass / M.Mass

Putting values,

Moles = 10.0 g / 30.07 g/mol

Moles = 0.3325 moles

Step 2: Calculate Moles of CO₂ as;

According to balance chemical equation,

2 moles of C₂H₆ produced = 4 moles of CO₂

So,

0.3325 moles of C₂H₆ will produce = X moles of CO₂

Solving for X,

X = 0.3325 mol × 4 mol ÷ 2 mol

X = 0.665 moles of CO₂

3 0

3 years ago