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2 years ago

How old is the universe

Chemistry

2 answers:

ehidna [41]2 years ago

5 0

13.8 billion years old

snow_lady [41]2 years ago

5 0

Answer:

The earth is around 6,000 years old. It cannot scientifically be 14 billion years old because earth is slowing down, this means it used to be going faster. This makes it so that carbondating cannot work because of the magnetic field and that if dinasaurs lived millions of years ago they wouldn't have gotten hit by an asteroid, they would've just flew off the earth.

Explanation:

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According to the Lewis model of acids and bases, amines behave as bases in water because __________. View Available Hint(s) Acco

lyudmila [28]

Answer: the unshared pair of electrons on the nitrogen can accept a proton

Explanation:

According to the Lewis concept, an acid is defined as a substance that accepts electron pairs and base is defined as a substance which donates electron pairs.

Amines have a general molecular formula of $RNH_2$ which has lone pair of electrons on nitrogen and thus is able to donate electrons to a lewis acid which is short of electrons. In other words nitrogen can accept a proton.

$RNH_2+H^+\rightarrow RNH_3^+$

7 0

2 years ago

What mass of magnesium would combine with exactly 16.0 grams of oxygen

TEA [102]

1.65g MgO = 1g Mg
1.65 - 1 = 0.65 g of O in MgO

solve it using proportion:
1g Mg / 0.65g O = x (g) Mg / 16g O
or 1 / 0.65 = x / 16

24.6 g is the answer.

if 1 gram of oxygen requires 1.65 grams of Mg
then 16 grams of oxygen will require 16 ( 1.65) or 26.4 grams.

3 0

3 years ago

Please give me the reasons of the solution!

irinina [24]

1. The answer is option E, that is None of the above is correct.

As a polymer becomes more crystalline,

its melting point doesn't decreases, its density doesn't decreases, its stiffness doesn't decreases and its yield stress doesn't decreases.

2. The answer is option B, that is the molecules are arranged in sheets, with their long axes parallel and their ends aligned as well.

In the smectic A liquid-crystalline phase, molecules are arranged in sheets, with their long axes parallel and their ends aligned as well.

3. For a substitutional alloy to form, the two metals combined must have similar atomic radii and chemical bonding properties.

6 0

2 years ago

Identify the atomic orbitals in the C-C sigma bond in ethyne (acetylene HC-triplebond-CH)

aleksley [76]

Answer:

Explanation:

A sigma bond is formed when a hybrid orbital sp overlaps with another hybrid orbital or with s- or p- orbital

Ethylene has a structural formula of H - C≡ C- H

At the ground state; we have :

C | ⇅ | |↑ | ↑

2s 2p

At the excited state, we have:

C | ↑ | |↑ | ↑ | ↑

the hybrid orbital

C = | ↑ | ↑ |

2sp

8 0

3 years ago

write a balanced chemical equation for each single replacement reaction that takes place in aqueous solution. write no reaction

Illusion [34]

The question is incomplete, here is the complete question:

Write a balanced chemical equation for each single replacement reaction that takes place in aqueous solution. write no reaction if a reaction does not occur

1.) Zn + PbCl₂

2.) Cu + Fe(NO₃)₂

Answer:

For 1: The reaction does occur.

For 2: The reaction does not occur.

Explanation:

Single displacement reaction is defined as the reaction in which more reactive element displaces a less reactive element.

The reactivity of metal is determined by a series known as reactivity series. The metals lying above in the series are more reactive than the metals which lie below in the series.

$A+BC\rightarrow AC+B$