All categories

3 years ago

When an iron nail is ground into powder, its mass ____.

Chemistry

1 answer:

Gre4nikov [31]3 years ago

3 0

Explanation:

(a) The mass of an object remains the same always. It is independent of its location. In this case, an iron nail is ground into powder. It means that its mass will remain unchanged. Hence, (a) is the correct option.

(b) Whenever there is a change of color of an object, a chemical reaction occurs. It shows that a reaction happens there. In this problem, a paper turns yellow-brown upon exposure to sunlight. A chemical reaction takes place there. Hence, (b) is the correct option.

You might be interested in

) What effect does the attraction among Earth, the moon, and the sun cause?

Jobisdone [24]

Answer:

earth is were humans live for live and the moon controls the water and the sun gives heat for us humans and plants and life

Explanation:

7 0

2 years ago

Illustrate the x- and y-axes to show the reaction pathway and potential energy, in kilojoules. Ensure your energy intervals are

Rufina [12.5K]

Answer:

Enthalpy of a reaction = P - R

Synthesis: ΔH = 25 kJ - (-30 kJ) = 55 kJ

Single Replacement: ΔH = 30kJ - 65 kJ = -35 kJ

Double Replacement: ΔH = 60 kJ - 10 kJ = 50 kJ

Explanation:

6 0

3 years ago

How is the law of conservation of mass shown by a balanced chemical equation?

valina [46]

Answer:

Matter cannot be created or destroyed in chemical reactions. This is the law of conservation of mass. In every chemical reaction, the same mass of matter must end up in the products as started in the reactants. Balanced chemical equations show that mass is conserved in chemical reactions.

Hope this helps! (:

7 0

3 years ago

✯Hello✯☆(❁‿❁)☆

sveticcg [70]

do you mean fractional distillation of crude oil ?

if you do then this is what happens:

basically, crude oil is made up of a lot of hydrocarbons so it's put into a fracitonating column to separate these compounds into fractions. the top of the fractionating column is colder whereas the bottom of the column is hotter.

gases, petrol, diesel and kerosene come out near the top of the top of the column because they are shorter chains. substances near the top of the column also have a lower boiling point (since it's cooler and there's less intermolecular forces).

the substances at the top of the column are typically useful fuels because they have a higher ease of ignition (higher up=easier to ignite, lower down = harder to ignite). Also, substances at the top have a low viscosity so they can flow easily.

substances that come out near the bottom of the fracitonating column include fuel oil and bitumen.

these are longer chains of hydrocarbons and bitumen is used for road surfacing.

these substances have a high viscosity (harder to flow) and have a high boiling point since they have more intermolecular forces which require a lot of energy to break. Also the bottom of the fractionating column is warmer and this is where these fractions are released.

5 0

3 years ago

Hich one of the following statements about orbital hybridization is incorrect?

photoshop1234 [79]

Answer : The incorrect statement is, (C) The nitrogen atom in NH₃ is sp² hybridized.

Explanation :

Formula used :

$\text{Number of electron pair}=\frac{1}{2}[V+N-C+A]$

where,

V = number of valence electrons present in central atom

N = number of monovalent atoms bonded to central atom

C = charge of cation

A = charge of anion

Now we have to determine the hybridization of the following molecules.

(a) The given molecule is, $CH_4$

$\text{Number of electrons}=\frac{1}{2}\times [4+4]=4$

The number of electron pair are 4 that means the hybridization will be $sp^3$ and the electronic geometry of the molecule will be tetrahedral.

(b) The given molecule is, $CO_2$

$\text{Number of electrons}=\frac{1}{2}\times [4]=2$

The number of electron pair are 2 that means the hybridization will be $sp$ and the electronic geometry of the molecule will be linear.

(c) The given molecule is, $NH_3$

$\text{Number of electrons}=\frac{1}{2}\times [5+3]=4$

The number of electron pair are 4 that means the hybridization will be $sp^3$ and the electronic geometry of the molecule will be tetrahedral.

But as there are 3 atoms around the central nitrogen atom, the fourth position will be occupied by lone pair of electrons. The repulsion between lone and bond pair of electrons is more and hence the molecular geometry will be trigonal pyramidal.

(d) sp² hybrid orbitals are coplanar, and at 120° to each other.

The sp² hybrid orbitals has trigonal planar geometry and are in the same plane that means coplanar. Thus, the bond angle is 120° to each other.

(e) sp hybrid orbitals lie at 180° to each other.

The sp hybrid orbitals has linear geometry. Thus, the bond angle is 180° to each other.

Hence, the incorrect statement is, (C) The nitrogen atom in NH₃ is sp² hybridized.

4 0

3 years ago