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3 years ago

Which of the following does NOT indicate that a chemical change may have taken place?

Chemistry

2 answers:

sineoko [7]3 years ago

4 0

Answer: Option (a) is the correct answer.

Explanation:

Chemical changes are defined as the change which tend to show difference in chemical composition of a substance.

For example, toxicity, reactivity, combustion, change in energy, precipitation etc are all chemical properties.

A chemical change will always lead to the formation of a new compound and this change is irreversible in nature by any physical means.

On the other hand, a change which is unable to bring any difference in chemical composition of a substance is known as a physical change.

For example, change in shape, size, mass, volume etc are all physical properties.

Thus, we can conclude that out of the given options fracture formation does NOT indicate that a chemical change may have taken place.

labwork [276]3 years ago

3 0

The following does NOT indicate that a chemical change may have taken place is fracture formation. A chemical change happens when the substance changes its physical state and composition resulting from a chemical reaction. This chemical reaction may either give off or absorb energy. A change in color is a chemical change. For example, litmus paper turns to red when placed in an acid solution. Production of gas is a chemical change. For example, adding hydrochloric acid to the tiles of the bathroom gives a hissing sound with gases given off. Formation of a precipitate is also a chemical change. Change in shape is not a chemical change.

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During our phase changes lab, where did we place the thermometer?

IrinaK [193]

The thermometer must be in contact with the ice/water only

Explanation:

In this experiment in the lab, the aim is to measure the specific latent heat of fusion of water.

The specific latent heat of fusion of a substance is the amount of heat energy required to completely melt a certain amount of the substance, mathematically:

$\lambda = \frac{Q}{m}$

where

Q is the heat supplied to the substance

m is the mass of the substance

In this experiment, the aim is to measure the specific latent heat of fusion of water. In order to do that, a mix of ice/water is heated with a certain amount of heat Q, and then it is evaluated the amount of mass m that undergoes melting.

An important precaution that must be taken in this experiment is that the temperature of the water/ice mixture remains constant and equal to the melting point of ice (otherwise, part of the heat supplied to the mixture is used to increase the temperature of the water, resulting in an inaccurate measure of Q). Therefore, a thermometer must be used to check constantly the temperature, and this thermometer must be placed inside the ice/water mixture only (It should not touch the saucepan, whose temperature can be higher).

So, the correct answer is

in contact with the ice/water only

Learn more about specific heat:

brainly.com/question/3032746

brainly.com/question/4759369

#LearnwithBrainly

3 0

3 years ago

4NH3 + 3O2 --> 2N2 + 6H2O

larisa86 [58]

The balanced reaction is:

4NH3 + 3O2 --> 2N2 + 6H2O

We are given the amount of reactants to be used for the reaction. This will be the starting point of our calculation.

83.7g of O2 ( 1 mol / 32 g) = 2.62 mol O2

2.81 moles of NH3

From the balanced reaction, we have a 4:3 ratio of the reactants. The limiting reactant would be oxygen. We will use the amount for oxygen for further calculations.

2.62 mol O2 (6 mol H2O / 3 mol O2) (18.02 g H2O / 1 mol H2O) = 94.42 g H2O

8 0

3 years ago

What force is the type of intermolecular force that would be present between molecules of Cl2 ?

KatRina [158]

Cl2 is nonpolar so it has to be only London dispersion force (LDF)

7 0

3 years ago

Read 2 more answers

The pre-exponential constant and activation energy for the diffusion of iron in cobalt are 1.7 x 10-5 m2/s and 273,300 J/mol, re

Kitty [74]

Answer: The temperature of the system will be 1622 K

Explanation:

The equation relating the pre-exponential factor and activation energy follows:

$\log D=\log D_o-\frac{E_a}{2.303RT}$

where,

D = diffusion coefficient = $2.7\times 10^{-14}m^2/s$

$D_o$ = pre-exponential constant = $1.7\times 10^{-5}m^2/s$

$E_a$ = activation energy of iron in cobalt = 273,300 J/mol

R = Gas constant = 8.314 J/mol.K

T = temperature = ?

Putting values in above equation, we get:

$\log (2.7\times 10^{-14})=\log (1.7\times 10^{-5})-\frac{273,300}{2.303\times 8.314\times T}\\\\T=1622K$

Hence, the temperature of the system will be 1622 K

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3 years ago

The function of a specific enzyme is mostly determined by its

galben [10]

Answer:

What does the shape of an enzyme determine? The shape of the enzyme determines which chemical reaction it will speed up. -The region on an enzyme that the substrate fits into. ... The active site of an enzyme only fits one type of substrate molecule.

Explanation:

7 0

2 years ago