3- Our stomachs contain hydrochloric acid (pH 1.5-3.5). Why do you suppose this

QuesLUI 2 UI IU

Alika [10]

Answer:

D) The given reaction is Exothermic, because energy is released

Explanation:

Here, given that Zinc is added to a beaker containing hydrochloric acid.

Also, the beaker gets warm.

⇒The energy is released in the form of heat.

EXOTHERMIC reactions are those type of reactions in which energy is released in the form of heat.

When the beaker gets warm, the reaction is exothermic in nature.

Hence, the given reaction is Exothermic, because energy is released

3 0

3 years ago

Bob is pulling a 30kg filing cabinet with a force of 200n , but the filing cabinet refuses to move. the coefficient of static fr

puteri [66]

The cabinet is being pulled with 200N and is being rested by a force equal to 200N. That is why it is not being moved.

<span>Although the force of static friction can equal Fk=µs*F=m*g*µs=(30kg)*(9.8m/s^2)*(0.80)=235 N. It is not resisting the 200N force with 235N. Imagine if you pushed something with 200N and it pushed you back with 235N, especially a cabinet. You would think that the cabinet was alive.</span>

8 0

3 years ago

A cube that is 20 nanometer on an edge contains 399,500 silicon atoms, and each silicon atom has 14 electrons and 14 protons. In

Sergeu [11.5K]

Answer:

Total 3 holes are available for conduction of current at 300K.

Explanation:

In order to develop a semiconductor, two type of impurities can be added as given below:

N-type Impurities: Pentavalent impurities e.g. Phosphorous, Arsenic are added to have an additional electron in the structure. Thus a pentavalent impurity creates 1 additional electron.
P-type Impurities: Trivalent impurities e.g. Boron, Aluminium are added to have a positive "hole" in the structure. Thus a trivalent impurity creates 1 hole.

Now for estimation of extra electrons in the impured structure is as

$N_{electrons-free}=n_{pentavalent \, atoms}\\N_{electrons-free}=4\\$