All categories

3 years ago

What are the signs that a chemical reaction has occurred

Chemistry

2 answers:

Finger [1]3 years ago

8 0

Well. There is the color change and the formation of bubbles.

MrRa [10]3 years ago

8 0

Color change, formation of a precipitate, heat, formation of a gas, and odor

You might be interested in

What are the Lewis definitions of an acid and a base? In what way are Bronsted definitions? they more general than the In terms

kati45 [8]

Explanation:

Lewis definition of Acids and Bases

Chemical species which are capable of accepting electron pairs or donating protons are called Lewis acid.

Chemical species which are capable of donating electron pairs or accepting protons are called Lewis base.

Bronsted definition of acids and bases

Chemical species which are capable of donating H+ are called Bronsted acids.

Chemical species which are capable of accepting H+ are called Bronsted bases.

So all Bronsted acids are Lewis acids but all Lewis acids are not Bronsted acids.

For a chemical species to behave as Lewis acid, they must have:

Incomplete octet
Double bond
Vacant d-orbitals

For example, in BF3, octet of boron is incomplete, so it can accept a pair of electron and behaves as Lewis acid.

For a chemical species to behave as Lewis base, they must have:

lone pair of electrons

For example, NH3 and OH, both N and O have lone pairs of electrons, hence behave as Lewis base.

4 0

3 years ago

A 0.529-g sample of gas occupies 125 ml at 60. cm of hg and 25°c. what is the molar mass of the gas?

Llana [10]

Let's assume that the gas has ideal gas behavior. 
Then we can use ideal gas formula,
PV = nRT

Where, P is the pressure of the gas (Pa), V is the volume of the gas (m³), n is the number of moles of gas (mol), R is the universal gas constant ( 8.314 J mol⁻¹ K⁻¹) and T is temperature in Kelvin.

P = 60 cm Hg = 79993.4 Pa
V = 125 mL = 125 x 10⁻⁶ m³

n = ?

R = 8.314 J mol⁻¹ K⁻¹
T = 25 °C = 298 K

By substitution,
79993.4 Pa x 125 x 10⁻⁶ m³ = n x 8.314 J mol⁻¹ K⁻¹ x 298 K
n = 4.0359 x 10⁻³ mol

Hence, moles of the gas = 4.0359 x 10⁻³ mol

Moles = mass / molar mass

Mass of the gas = 0.529 g

Molar mass of the gas = mass / number of moles
= 0.529 g / 4.0359 x 10⁻³ mol
 = 131.07 g mol⁻¹

Hence, the molar mass of the given gas is 131.07 g mol⁻¹

4 0

3 years ago

nitrogen is made up of two isotopes N-14 and N15. given nitrogen’s atomic weight of 14.007 what is the percent abundance of each

Oduvanchick [21]

The answer is n14 if it

8 0

3 years ago

Which of the following best describes the difference in bonding between two hydrogen atoms and two carbon atoms?

valentinak56 [21]

Answer :

2. Hydrogen forms bonds through the overlap of 1s atomic orbitals and the sharing of electrons between atoms. Carbon forms bonds through the overlapping of sp hybrid atomic orbitals and the sharing of electrons between carbon atoms.

Explanation:

The H-H bond is formed by the overlap of two 1s orbitals and the sharing of electrons between the two atoms.

A carbon atom must use the overlap of hybridized atomic orbitals and the sharing of electrons to bond with another carbon atoms.

1. is wrong because H can use only its 1s orbital for bonding.

3. is wrong because C must share electrons to form a carbon-carbon bond.

4. is wrong because C does NOT use overlapping of 2s orbitals for bonding. It uses the overlap of hybridized orbitals.

5. is wrong because H must share electrons to form an H-H bond.

4 0

3 years ago

It requires energy to melt ice. Applying salt to the ice created a chemical reaction melting the ice. Were did the energy come f

Ilia_Sergeevich [38]

Answer:

HOPE IT HELPS...

Explanation:

When added to ice, salt first dissolves in the film of liquid water that is always present on the surface, thereby lowering its freezing point below the ices temperature. Ice in contact with salty water therefore melts, creating more liquid water, which dissolves more salt, thereby causing more ice to melt, and so on

4 0

2 years ago