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solmaris [256]
2 years ago
13

1. What is the geologic time scale? Explain how the geologic time scale is a model.

Chemistry
2 answers:
oksano4ka [1.4K]2 years ago
6 0
This is the answer hope it will help you
tiny-mole [99]2 years ago
5 0
1.) the geologic time scale is a system of chronological dating that relates geologic structure to geologic events. it is a model because it measures and describes events and relationships in geologic history.

2.) the paleozoic period was roughly from 245 million years ago to 545 million years ago.

3.) the dinosaurs lived in the mesozoic era, specifically the triassic period, which was roughly around 230 million years ago.

4.) the first early human relatives were found roughly around d the neogene period, about 25 million years ago, and is in the cenozoic era.
You might be interested in
4-hydroxypentanal reacts with one equivalent of methanol to form a cyclic acetal.
quester [9]

Answer:

Explanation:

The equation is given as:

CH3CHOHC2H4CHO + CH3OH --> CYCLIC ACETAL + H2O

This above equation is carried out in the presence of a strong acid. There are five mechanisms employed and they are:

Step 1:

Initial formation of the hemiacetal which takes several steps

Step 2:

Addition of a proton. The hemicetal is protonated on the hydroxyl group (-OH group)

Step 3:

As seen a bond is broken to give the H2O molecule and a resonance stabilized cation.

The carbonyl group on the cation is enriched with the oxygen-18 got from the H2O molecule as seen in the mechanism.

Step 4:

An attraction occurs between electrophile and nucleophile i.e the stabilised cation and the lone paids of the methanol.

Step 5:

Finally, a proton (+) is removed from the molecule by a lone pair of electron on the methanol.

Attached are the Steps 1 - 5 mechanism below

4 0
3 years ago
A 40.2 g sample of a metal heated to 99.3°C is placed into a calorimeter containing 120 g of water at 21.8°C. The final temper
aliina [53]

Answer:

B) Iron (c=0.45 J/g°C)

Explanation:

Given that:-

Heat gain by water = Heat lost by metal

Thus,  

m_{water}\times C_{water}\times (T_f-T_i)=-m_{metal}\times C_{metal}\times (T_f-T_i)

Where, negative sign signifies heat loss

Or,  

m_{water}\times C_{water}\times (T_f-T_i)=m_{metal}\times C_{metal}\times (T_i-T_f)

For water:

Mass = 120 g

Initial temperature = 21.8 °C

Final temperature = 24.5 °C

Specific heat of water = 4.184 J/g°C

For metal:

Mass = 40.2 g

Initial temperature = 99.3 °C

Final temperature = 24.5 °C

Specific heat of metal = ?

So,  

120\times 4.184\times (24.5-21.8)=40.2\times C_{metal}\times (99.3-24.5)

40.2C_{metal}\left(99.3-24.5\right)=120\times \:2.7\times \:4.184

40.2C_{metal}\left(99.3-24.5\right)=1355.616

C_{metal}=0.45\ J/g^0C

<u>This value corresponds to iron. Thus answer is B.</u>

3 0
3 years ago
Which of the following is an electrolyte?. A) potassium chloride. B) glucose. C) water D) mayonnaise.
kenny6666 [7]
Answer A )

Potassium chloride

K+   Cl-

hope this helps!.
8 0
3 years ago
What is the valence of K2O2
raketka [301]
14 since K has 1 valence but there’s two so 2 valence for k and oxygen has 6 but there’s two so 12
6 0
3 years ago
a sample of ammonia liberates 5.66 kj of heat as it solidifies at its melting point . what is the mass of the sample?
Reil [10]
The correct answer for the question that is being presented above is this one: "<span>16.728 g."</span>

Given that 
ΔHsolid = -5.66 kJ/mol.
This means that 5.66 kJ of heat is released when 1 mole of NH3 solidifies 

When 5.57 kJ of heat is released
amount of NH3 solidifies = 5.57/5.66 = 0.984 moles 

<span>molar mass of NH3 = 17 g/mole </span>
<span>1 mole of NH3 = 17 g </span>
So, 0.984 moles of NH3 = 17 X 0.984 = 16.728 g
7 0
3 years ago
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