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3 years ago

Which statements describe the principles of the big bang theory? Check all that apply.

2 answers:

8 0

The big bang theory explains how the universe began. According to it, the universe began as singularity (a very hot , small and dense superforce with no stars, atoms, or structures) and then about 13.7 billion years ago, the space expanded very quickly. This leads to formation of stars and galaxies which we know today. This expanding of universe is still happening and thus the temperature of universe is decreasing.

Therefore, the statements describing the bing bang theory are:

1) The universe is continuing to expand and

2)A massive explosion caused matter and energy to expand and form the universe.

amid [387]3 years ago

5 0

Answer:

The Universe is continuing to expand.

A Massive explosion caused matter and energy to be destroyed.

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An experiment to measure the enthalpy change for the reaction of aqueous

Komok [63]

Given that, an experiment to measure the enthalpy change for the reaction of aqueous copper(II) sulfate, CuSO4(aq) and zinc, Zn(s) was carried out in a coffee cup calorimeter; the heat of the reaction in the whole system is calculated to be 2218.34 kJ

Heat of reaction (i.e enthalpy of reaction) is the quantity of heat that is required to be added or removed when a chemical reaction is taken place in order to maintain all of the compounds present at the same temperature.

The formula used to calculate the heat of the reaction can be expressed as follows:

Q = mcΔT

where:

Q = quantity of heat transfer
m = mass
c = specific heat of water = 4.18 kJ/g °C (constant)
ΔT = change in temparature

From the information given:

The initial temperature (T₁) = 25° C
The final temperature (T₂) = 91.5° C

∴

The change in temperature i.e. ΔT = T₂ - T₁

ΔT = 91.5° C - 25° C

ΔT = 66.5° C

The number of moles of CuSO₄ = 1.00 mol/dm³ × 50.0 cm³

$\mathbf{= (1 \times \dfrac{50}{1000})\ moles}$

= 0.05 moles

Since the molar mass of CuSO₄ = 159.609 g/mol

Then;

Using the relation:

$\mathbf{number \ of \ moles = \dfrac{mass}{molar \ mass}}}$

By crossing multiplying;

mass of CuSO₄ = number of moles of CuSO₄ × molar mass of CuSO₄

mass of CuSO₄ = 0.05 moles × 159.609 g/moles

mass of CuSO₄ = 7.9805 grams

∴

Using the formula from above:

Q = mcΔT

Q = 7.9805 g × 4.18 kJ/g °C × 66.5° C

Q = 2218.34 kJ

Therefore, we can conclude that the heat of the reaction is 2218.34 kJ

Learn more about the chemical reaction here:

brainly.com/question/20250226?referrer=searchResults

8 0

2 years ago

Is O2 always a double bond?

Dima020 [189]

O-O single bonds and H-O single bonds in $\text{H}_2\text{O}_2$ molecules.
H-O single bonds in $\text{H}_2\text{O}$ molecules.
O=O double bonds in $\text{O}_2$ molecules.

<h3>Explanation</h3>

How many valence electrons do atoms in each molecule need for them to be stable?

Each H atom needs two valence electrons to be stable.
Each atom of an element other than H needs eight valence electron to be stable.

There are two H atoms and two O atoms in an $\text{H}_2\text{O}_2$ molecule. Atoms in each $\text{H}_2\text{O}_2$ need $2 \times 1 + 2\times 2 = 6$ more electrons to be stable.
There are two H atoms and one O atom in an $\text{H}_2\text{O}$ molecule. Atoms in each $\text{H}_2\text{O}$ molecule need $2 \times 1 + 2= 4$ more electrons to be stable.
There are two O atoms in an $\text{O}_2$ molecule. Atoms in each $\text{O}_2$ molecule need $2 \times 2 = 4$ more electrons to be stable.

How many chemical bonds in each molecule?

Each chemical bond adds one valence electron to each bonding atom. Each chemical bond connects two atoms. As a result, each chemical bond adds two valence electrons to the molecule.

Each $\text{H}_2\text{O}_2$ molecule needs $6 / 2 = 3$ chemical bonds.
Each $\text{H}_2\text{O}$ molecule needs $4 / 2 = 2$ chemical bonds.
Each $\text{O}_2$ molecule needs $4 /2= 2$ chemical bonds.

What chemical bonds are these? Again, each H atom needs only one more valence electron to be stable. It will share only one electron with O and form one H-O bond. The rest of the chemical bonds are between O atoms.

There are two H atoms in each $\text{H}_2\text{O}_2$ molecule, which form two H-O bonds. Two of the three chemical bonds in this molecule are H-O. The other is an O-O single bond between the two O atoms.
There are two H atoms in each $\text{H}_2\text{O}$ molecule, which form two H-O bonds. Both chemical bonds in this molecule are H-O. There's no O-O bond in this molecule.
There is no H atom in $\text{O}_2$ molecules. Both chemical bonds are between O atoms. However, there are only two O atoms. There must be two chemical bonds between the two O atoms. That bond will be an O-O double bond.

3 0

2 years ago

Read 2 more answers

A teacher attaches two slinky springs to a fixed support. The springs are moved, as shown in the image. Wave A wave B What prope

Misha Larkins [42]

Answer:

a changes more because it going higher

Explanation:

6 0

2 years ago

Read 2 more answers

When matter is a gass, a lot of the time it is ____?

Zielflug [23.3K]

I’d say most likely air, oxygen, or carbon dioxide

6 0

3 years ago

Read 2 more answers

For many years chloroform (CHCl3) was used as an inhalation anesthetic in spite of the fact that it is also a toxic substance th

Debora [2.8K]

Hey there!:

Molar mass:

CHCl3 = ( 12.01 * 1 )+ (1.008 * 1 ) + ( 35.45 * 3 ) => 119.37 g/mol

C% = ( atomic mass C / molar mass CHCl3 ) * 100

For C :

C % = (12.01 / 119.37 ) * 100

C% = ( 0.1006 * 100 )

C% = 10.06 %

For H :

H% = ( atomic mass H / molar mass CHCl3 ) * 100

H% = ( 1.008 / 119.37 ) * 100

H% = 0.008444 * 100

H% = 0.8444 %

For Cl :

Cl % ( molar mass Cl3 / molar mass CHCl3 ):

Cl% = ( 3 * 35.45 / 119.37 ) * 100

Cl% = ( 106.35 / 119.37 ) * 100

Cl% = 0.8909 * 100

Cl% = 89.9%

Hope that helps!

4 0

3 years ago