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siniylev [52]
3 years ago
15

The fossil record is the record of life on earth preserved in rock as fossils. The fossil record provides evidence of what types

of plant and animals lived, how long they lived, how they died, and changed. It also tells us about Earth’s early environment, and how it changed. The fossil record helps determine the age of rock formations by looking at how deep the fossil are buried in the rock. When a fossil is found above another fossil in a rock formation, the deeper fossil are considered older.
What can scientists infer about a specific period of Earth's history if many fossils were discovered from oxygen-breathing organisms?
A) the atmosphere lacked oxygen
B) only fish lived during that time
C) the dinosaurs used all the oxygen
D) the atmosphere had lots of oxygen
Chemistry
2 answers:
Yuki888 [10]3 years ago
5 0

Answer:

the correct answer is d)

Explanation:

strojnjashka [21]3 years ago
3 0

Answer:

d is wrong the correct answer is b

Explanation:

The atmosphere lacked oxygen is correct. The lack of animals that used oxygen suggests that the environment did not have much oxygen.

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If a bonding pair of electrons is unequally shared between two atoms, the bond is
joja [24]
The answer is D. And if it is equally shared it is nonpolar covalent bond
4 0
3 years ago
Read 2 more answers
Which statements are correct about silicon?
ki77a [65]

Answer:

A. Metalloid

E. Has similar properties as Ge

F. Belongs to Period 3​

Explanation:

Silicon is the 14th element on the periodic table. Its unit is SI. Its properties straddles between those of metals and non-metals and it is described as a non-metal.

It's atomic weight or mass number is 28u. It has an atomic number of 14 i.e in its neutral state, the number of protons and electrons are equal to 14.

Silicon belongs to the 4th group and the 3rd period on the periodic table. Elements in the same group share similar chemical properties. The elements in Si group are: C, Ge, Sn and Pb. The properties of Si is similar to these elements because they all have a valency of 4. Across the period, the properties varies this is why Si would have a very different property from Al and P.

4 0
3 years ago
What is the theoretical yield of NaBr
dolphi86 [110]

The theoretical yield of NaBr given that 2.36 moles of FeBr₃ reacts is 7.08 moles

<h3>Balanced equation </h3>

2FeBr₃ + 3Na₂S → Fе₂S₃ + 6NaBr

From the balanced equation above,

2 moles FeBr₃ reacted to produce 6 moles of NaBr

<h3>How to determine the theoretical yield of NaBr</h3>

From the balanced equation above,

2 moles FeBr₃ reacted to produce 6 moles of NaBr

Therefore,

2.36 moles FeBr₃ will react to produce = (2.36 × 6) / 2 = 7.08 moles of NaBr

Therefore,

Thus, the theoretical yield of NaBr is 7.08 moles

Learn more about stoichiometry:

brainly.com/question/14735801

#SPJ1

7 0
2 years ago
Assuming the relative rate of secondary hydrogen atom abstraction for the chlorination of propane is 3.9 times faster than the r
Ghella [55]

Answer:

% of n-propyl chloride = 43.48 %

Explanation:

There are 2 secondary hydrogens and 6 primary hydrogens

The rate of abstraction of seondary hydrogen = 3.9 X rate of abstraction of primary hydrogen

probability of formation of isopropyl chloride = 3.9 X 1 (relative rate X relative number of secondary hydrogens)

Probability of formation of n-propyl chloride = 1 X 3 (relative rate X relative number of primary hydrogens)

Total probability = 3.9

% of n-propyl chloride = 3 X 100 / 6.9 = 43.48 %

7 0
3 years ago
Please I don’t get this at all someone help
ohaa [14]
I think it’s 7.41 because you count up all the atoms and find out how many are x (the large grey ones) and you do 2/27 x 100 which gives you 7.41 :) (sorry if i counted wrong it’s kinda hard)
6 0
3 years ago
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