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3 years ago

What happens to the chemical identity of a substance during a physical change?

1 answer:

5 0

Nothing happens because a physical change only changes the appearance of the substance, whereas a chemical change transforms the substance into something completely different.
i.e. (chemical change) wood + fire = ash
(physical change) wood + axe = smaller pieces of wood

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Forces that change an object motion by touching the object are _______ forces

strojnjashka [21]

Forces are pushes and pulls that may change the motion of an object. Balanced forces result in an object remaining at rest or moving at a constant speed. Unbalanced forces result in the acceleration of an object. An object's motion depends on how it changes position.

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3 years ago

What are three applications of the coal

labwork [276]

Three uses of coal:

1. Electricity generation

2. Steel production

3. Cement manufacturing and as a liquid fuel

Hope it helps!

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2 years ago

How would you prepare 3.5 L of a 0.9M solution of KCl?

PolarNik [594]

$V=3,5L\\
Cm=0,9M\\
M_{KCl}=74\frac{g}{mol}\\\\
C_{m}=\frac{n}{V}\\\\
n=\frac{m}{M}\\\\
C_{m}=\frac{m}{MV} \ \ \ \Rightarrow \ \ \ m=C_{m}MV\\\\
m=0,9\grac{mol}{L}*74\frac{g}{mol}*3,5L=233,1g$

B. Add 233 g of KCl to a 3.5 L container; then add enough water to dissolve the KCl and fill the container to the 3.5 L mark.

4 0

3 years ago

A ____________ alkene is more stable than a ____________ alkene because they have fewer steric interactions. In an elimination r

Vesna [10]

Answer:

See explanation

Explanation:

A trans alkene is more stable than a cis alkene because they have fewer steric interactions.

⇒ In a cis alkene there is steric hindrance, because the methyl groups are on the same side of the double bond.

Because of this steric crowding, there are van der Waals repulsive forces between the electron clouds of the groups.

This decreases the stability of the cis alkene.

In an elimination reaction, a geometry where the β hydrogen and the leaving group are on opposite sides of the molecule is called anti periplanar.

⇒ 'Anti’ refers to the two functional groups lying on opposite sides of the plane of the bond

In an SN1 mechanism, a nucleophile attacks the carbocation, forming a substitution product,

⇒ The SN1 reaction is a substitution reaction, and means "nucleophilic substitution".The "1" says that the rate-determining step is unimolecular. Thus, the rate equation is often shown as having first-order dependence on electrophile and zero-order dependence on nucleophile.

while in an E1 mechanism, a base removes a β hydrogen from the carbocation, forming a new π-bond.

⇒ E1 indicates a elimination, unimolecular reaction

This implies that the rate determining step of the mechanism depends on the decomposition of a single molecular species.

.This is a classic elimination reaction – forming a new C–C(π) bond, and breaking a C–H and C–leaving group bond.

CH3CH2Br and NaOH react by an SN2 mechanism.

⇒ It's a type of reaction mechanism that is common in organic chemistry, where one bond is broken and one bond is formed, synchronously, (in one step.)

Stronger bases, like hydroxide, favor E2 reactions, whereas weaker bases, like water favor, E1 reactions

Disubstituted alkenes always have the possibility to exist as two different Diastereomer.

Diastereomer are stereoisomers that are not mirror images of one another and are non-superimposable on one another. They exist (always) in 2 forms.

Elimination reactions are regioselective, favoring formation of the more substituted and more stable alkene.

6 0

3 years ago

Determine whether each substance will sink or float in corn syrup, which has a density of 1.36 g/cm3. Write “sink” or “float” in

kondor19780726 [428]

Answer:

Here's what I get

Explanation:

A substance with ρ < 1.36 g/cm⁻³ will float on corn syrup.

A substance with ρ > 1.36 g/cm⁻³ will sink in corn syrup

$\begin{array}{rrr}\textbf{Substance} & \mathbf{\rho/g\cdot \textbf{cm}^{-3}}& \textbf{Sink/Float}\\\text{Gasoline} & 0.75 & \text{Float}\\\text{Water} & 1.00 & \text{Float}\\\text{Corn syrup} & 1.36 & -\\\text{Honey} & 1.42 & \text{Sink}\\\text{Titanium} & 4.54 & \text{Sink}\\\end{array}$

5 0

3 years ago

Read 2 more answers