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Yuliya22 [10]
3 years ago
8

Please Help Thank You

Chemistry
2 answers:
Stells [14]3 years ago
7 0
Its gonna be to learn about history on earth
Nikitich [7]3 years ago
5 0
The first option is the correct answer. Fossils belong to dinosaurs that lived in B.C/A.D, which scientists study to learn about Earth's prehistoric times.
You might be interested in
What do you look at to tell the reactivity of an atom?
tia_tia [17]

Answer:

The number of electrons in the outermost shell of an atom determines its reactivity. Noble gases have low reactivity because they have full electron shells. Halogens are highly reactive because they readily gain an electron to fill their outermost shell.

Explanation:

I hope this helped!

8 0
3 years ago
Which of the four solutions is the best buffer against addition of acid or base?
Vera_Pavlovna [14]

b. Na2HPO4 + NaH2PO4.

A <em>buffer </em>is a solution of a weak acid and its conjugate base. The weak acid is H2PO4^(-) and its conjugate base is HPO4^(2-).

All the other options are incorrect because they consist of only a single component.

8 0
3 years ago
Consider the first-order reaction shown here. the yellow spheres in the pictures to the right represent the reactant,
Luda [366]
The rate constant of the reaction K we can get it from this formula:

K=㏑2/ t1/2 and when we have this given (missing in question):
that we have one jar is labeled t = 0 S and has 16 yellow spheres inside and the jar beside it labeled t= 10 and has 8 yellow spheres and 8 blue spheres and the yellow spheres represent the reactants A and the blue represent the products B

So when after 10 s  and we were having 16 yellow spheres as reactants and becomes 8 yellow and 8 blue spheres as products so it decays to the half amount so we can consider T1/2 = 10 s
a) by substitution in K formula:
∴ K = ㏑2 / 10 = 0.069 
The amount of A (the reactants) after N half lives = Ao / 2^n
b) so no.of yellow spheres after 20 s (2 half-lives) =  16/2^2 = 4
and the blue spheres = Ao - no.of yellow spheres left = 16 - 4 = 12
c) The no.of yellow spheres after 30 s (3 half-lives) = 16/2^3 = 2
and the blue spheres = 16 - 2 = 14

8 0
3 years ago
The proper name for a carbohydrate polymer with 2 subunits is
valentina_108 [34]
Carbohydrates are classified in three major categories depending upon the number of sub units joining to form them. These are,

                                                Monosaccharides

                                                Oligosaccharides

                                                Polysachharides

The simplest single units are monosaccharides, if units are ranging between two and twenty they are called oligosaccharides and above twenty joining units they are called polysachharides.

Result:
          <span>The proper name for a carbohydrate polymer with 2 subunits is called Oligosachharide in general and Disaccharide in specific.</span>
8 0
3 years ago
"in the cores of extremely hot red giants, nuclear reactions convert helium to ____.
Sergeu [11.5K]

Red giants produce "metals", i.e., heavier elements.

The first step is helium conversion into

<span>carbon</span>

6 0
3 years ago
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