1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Leya [2.2K]
3 years ago
12

Is this true or false ?

Chemistry
2 answers:
Natali5045456 [20]3 years ago
8 0

Answer:

False. Atom models have changed in the past centuries.

stiks02 [169]3 years ago
7 0

Answer:

false

Explanation:

The atom model has changed over time because of the discovery of subatomic particles

You might be interested in
If an ice cube weighing 25.0 g with an initial
riadik2000 [5.3K]

Answer:

11

∘

C

Explanation:

As far as solving this problem goes, it is very important that you do not forget to account for the phase change underwent by the solid water at

0

∘

C

to liquid at

0

∘

C

.

The heat needed to melt the solid at its melting point will come from the warmer water sample. This means that you have

q

1

+

q

2

=

−

q

3

(

1

)

, where

q

1

- the heat absorbed by the solid at

0

∘

C

q

2

- the heat absorbed by the liquid at

0

∘

C

q

3

- the heat lost by the warmer water sample

The two equations that you will use are

q

=

m

⋅

c

⋅

Δ

T

, where

q

- heat absorbed/lost

m

- the mass of the sample

c

- the specific heat of water, equal to

4.18

J

g

∘

C

Δ

T

- the change in temperature, defined as final temperature minus initial temperature

and

q

=

n

⋅

Δ

H

fus

, where

q

- heat absorbed

n

- the number of moles of water

Δ

H

fus

- the molar heat of fusion of water, equal to

6.01 kJ/mol

Use water's molar mass to find how many moles of water you have in the

100.0-g

sample

100.0

g

⋅

1 mole H

2

O

18.015

g

=

5.551 moles H

2

O

So, how much heat is needed to allow the sample to go from solid at

0

∘

C

to liquid at

0

∘

C

?

q

1

=

5.551

moles

⋅

6.01

kJ

mole

=

33.36 kJ

This means that equation

(

1

)

becomes

33.36 kJ

+

q

2

=

−

q

3

The minus sign for

q

3

is used because heat lost carries a negative sign.

So, if

T

f

is the final temperature of the water, you can say that

33.36 kJ

+

m

sample

⋅

c

⋅

Δ

T

sample

=

−

m

water

⋅

c

⋅

Δ

T

water

More specifically, you have

33.36 kJ

+

100.0

g

⋅

4.18

J

g

∘

C

⋅

(

T

f

−

0

)

∘

C

=

−

650

g

⋅

4.18

J

g

∘

C

⋅

(

T

f

−

25

)

∘

C

33.36 kJ

+

418 J

⋅

(

T

f

−

0

)

=

−

2717 J

⋅

(

T

f

−

25

)

Convert the joules to kilojoules to get

33.36

kJ

+

0.418

kJ

⋅

T

f

=

−

2.717

kJ

⋅

(

T

f

−

25

)

This is equivalent to

0.418

⋅

T

f

+

2.717

⋅

T

f

=

67.925

−

33.36

T

f

=

34.565

0.418

+

2.717

=

11.026

∘

C

Rounded to two sig figs, the number of sig figs you have for the mass of warmer water, the answer will be

T

f

=

11

∘

C

Explanation:

3 0
3 years ago
What is Industrial chemistry?​
mel-nik [20]

Answer:

study of chemical used in industries

6 0
3 years ago
Jonas mixes citric acid with baking soda. How does he know the reaction is endothermic?
Kipish [7]

Answer:

D. The temperature of the the solution increases

Explanation:

Endothermic. Endo means in and thermic means a temperature, so Endothermic means the taking in of an temperature and the only answer choices that deal with temperature is,A and D. If it absorbs temperature it's going to rise.

6 0
3 years ago
Use the bond energy to calculate an approximate value of δh for the following reaction. Which is the more stable form of fno2?
professor190 [17]

The enthalpy of reaction or ∆H reaction is the difference between the bond energy of the reactants and the bond energy of the products.

<h3>What is ∆H reaction?</h3>

The term ∆H reaction refers to the heat that is evolved or absorbed in a chemical reaction. It is also known as the enthalpy of reaction.

The question is incoherent but I will try to answer as much as possible. Using the values of bond energy, ∆H reaction = Bond energy of reactants - bond energy of products. This will give us the enthalpy of reaction.

Learn more about bond energy: brainly.com/question/1657608

8 0
2 years ago
use the reaction that occours when magnesium burns in oxygen to show how a reaction might be included in more than one category
Schach [20]
2Mg+O₂⇒2MgO
It can be a combustion reaction, or it can be a combination reaction
5 0
3 years ago
Other questions:
  • From the Bohr equation in the introduction, the calculated energy of an electron in the sixth Bohr orbit of a hydrogen atom is
    10·1 answer
  • If you know the number of protons, how do you find the number of electrons
    12·1 answer
  • Which two atoms could be the "before'' and ''after'' of an alpha ejection
    9·1 answer
  • Many scientist compare the parts of a cell to the parts of a factory. Do you think this comparison is fair and useful?
    6·1 answer
  • What gives framework to a cell and helps it move
    8·2 answers
  • Solution 1 contains 3.5g of sodium chloride in 500 mL of water. Solution 2 contains 7.5g of glucose in 300 mL of water. If the a
    5·1 answer
  • How many moles of hydrogen molecules (h2) would be required to produce two moles of hydrogen peroxide (h2o2)?
    12·1 answer
  • ENERGY CANNOT BE CREATED<br> TRUE<br> False<br> Other:
    15·2 answers
  • In the Atomium building, what do the tubes represent?
    12·1 answer
  • Why are some amino acids described as essential amino acids?
    14·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!