What do repeated trials in an experiment allow a scientist to do?

How much heat is released when 75 g of octane is burned completely if the enthalpy of combustion is -5,500 kJ/mol CsH18? C8H18 +

aalyn [17]

Answer : The correct option is, (D) 3600 kJ

Explanation :

Mass of octane = 75 g

Molar mass of octane = 114.23 g/mole

Enthalpy of combustion = -5500 kJ/mol

First we have to calculate the moles of octane.

$\text{ Moles of octane}=\frac{\text{ Mass of octane}}{\text{ Molar mass of octane}}=\frac{75g}{114.23g/mole}=0.656moles$

Now we have to calculate the heat released in the reaction.

As, 1 mole of octane released heat = -5500 kJ

So, 0.656 mole of octane released heat = 0.656 × (-5500 kJ)

= -3608 kJ

≈ -3600 kJ

Therefore, the heat released in the reaction is 3600 kJ

5 0

2 years ago

Which of the following is not true of Mendel's experiment?

Karolina [17]

I believe it is B. Green pods are recessive.

5 0

2 years ago

Researchers tested a meteorite for organic molecules containing 13C and 15N, which are carbon and nitrogen atoms with one extra

Hoochie [10]

Answer:

The correct option is 2.No, because only electrons are involved in bonding.

Explanation:

The type of bond formed by carbon and nitrogen (carbon-nitrogen bond) is covalent bond

Also known as molecular bond, a covalent bond involves the sharing of pairs of electrons (known as bonding pairs or shared pairs) between the carbon and nitrogen atoms forming stable, balanced forces in attraction and repulsion as they share common electrons in their compounds.

This electron sharing covalent bond is what enables the formation of the several compounds between carbon and nitrogen for example, in an amine, nitrogen which has five electrons, has two remaining electrons that forms a lone pair whereby it can combine further with other elements.

Hence the factor that influences the bonds to make the numerous organic molecules is the available electrons which constitutes the shared electron pairs in covalent bonds while the neutrons which function is to keep the repulsive forces of positively charged protons from ripping the nucleus apart.

3 0

2 years ago

How many moles of hydrogen gas will be produced if 5.00 moles of zinc reactions with an excess amount of sulfuric acid

harkovskaia [24]

Answer:

Moles of Hydrogen produced is 5 moles

Explanation:

The balanced Chemical equation for reaction between zinc and sulfuric acid is :

$Zn(s) + H_{2}SO_{4}(aq) \rightarrow ZnSO_{4}(aq) + H_{2}(g)$

This equation tells that ; when 1 mole of Zn react with 1 mole of sulfuric acid, it produces 1 mole of zinc sulfate and 1 mole of hydrogen.

Since sulfuric acid is in excess so Zinc is the limiting reagent

(Limiting reagent : Substance which get consumed when the reaction completes, limiting reagent helps in predicting the amount of products formed)

Limiting reagent (Zn) will decide the amount of Hydrogen produced

$Zn(s) + H_{2}SO_{4}(aq) \rightarrow ZnSO_{4}(aq) + H_{2}(g)$

$1\ mole\ zinc\rightarrow 1\ mole\ H_{2}$

So,

$5\ mole\ zinc\rightarrow 5\ mole\ H_{2}$

Hence moles of Hydrogen produced is 5 moles

3 0

2 years ago

Can someone tell me how to differentiate if a given salt is acidic, basic, or neutral?

satela [25.4K]

$\bold{\huge{\underline{ Solution }}}$

<h3>Basic Characteristic of acids </h3>

Acids are sour in taste
Acid turns blue litmus paper or solution into red litmus paper or solution
Acids are good conductor of electricity because it dissociate into cation in aqueous solution
Acids classified into edible acids and non edible acids. Non edible acids are very hazardous
Generally, All acids are soluble in water
Acids have PH smaller than 7

Arrhenius definition of acids :-

According to Arrehinus,

Acids are those substances which when dissolve in water given H positive ions . Then, this hydrogen ions combine with water to form H30 + ions

Second definition of Acids was given by Bonsted Lowry :-

According to Bonsted Lowry

Acids are the proton donors that is when acids dissociate into water gives hydrogen ions that is H+ ions

3rd definition was given by Lewis 

According to Lewis

Acids are those substances which have the ability to accept a pair of electrons .

Example of Acids

HNO3 :- Nitric acid
H2SO4 :- Sulfuric acid
HCl :- Hydrochloric acid

<h3>Basic characterists of bases </h3>

Bases are bitter in taste
Bases turns red litmus paper into blue litmus paper or solution
Bases are also good conductor of electricity because on dissociation it produces anion in aqueous solution
Bases are also good conductor of electricity
When bases are soluble in water then they are known as alkaline base
Bases have PH greater than 7

Arrehinus definition of bases :-

According to Arrehinus ,

Bases are those substances which when dissolve in water produce OH negative ions that is hydroxide ions

Bonsted Lowry definition 

According to Bonsted Lowry

Bases are the proton donors as they produce OH negative ions in dissociation in aqueous solution

Lewis definition 

According to Lewis

Acids are those substances which have the ability to lose electrons that is they are electron donors.

Example of bases

Ca(OH)2 :- Calcium hydroxide
NaOH :- Sodium hydroxide
KOH :- Potassium hydroxide

[ Note :- There are so many Lewis acids and bases but they are not Arrhenius or Lowry acids or bases ]

<h3>Basic characteristic of salt </h3>

Salts are the ionic compounds which are composed of acids and bases that cation and anion
Salts are generally found in oceans and seas in the forms of crystals
As they are composed of acids and bases so they are neutral in nature but the salt of strong acid or weak base is acidic in nature or vice versa
Salts are also good conductor of electricity as they form ionic bond
Generally, All salts are soluble in water.
The PH of common Salt is 7

Example of salts

NH4Cl :- Ammonium chloride
CuSO4 :- Copper sulphate
NaCl :- Sodium chloride

6 0

2 years ago