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3 years ago

I have 2 questions:

2 answers:

7 0

The reactivity depends on the elements valence electrons. The need to be stable will make an element become more reactive, In order for an atom to be stable, it needs 8 valence electrons in its outer shell.

Since Calcium is in group 2, it has 2 valence electrons, and would rather give up the electrons. While Sulfur has 6, it would need to gain 2 more to be stable, making it more reactive.

kirill [66]3 years ago

6 0

An atoms valence is the amount of electrons in the outer ring and atoms like to have a valence of 8 so the closer to having 8 in the outer ring the more reactive the atom is so since both elements are 2 away from a valence of 8 theyre equally reactive

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52. In the following reaction, which are the Spectator ions? *

maks197457 [2]

Answer:

nitrate and sodium are spectator ions .The reactions that form an aqueous solution are often a spectator ions.

5 0

2 years ago

According to Chargaff's Rule, if a segment of DNA contains 60 cytosine bases out of a total of 300 bases how many thymine bases

bija089 [108]

Answer:

90 Thymine bases

Explanation:

Chargaff's rules states that in the DNA of any organism, the amount of purine and pyrimidine bases must be in a 1:1 ratio. This means that the amount of Adenine and Guanine bases (purines) should be equal with their complementary pairs of Thymine and Cytosine bases respectively (pyrimidines). (A = T) + (G = C) = 100

Hence, according to this question, if there are 60 cytosine bases, this means that there will be 60 Guanine bases. 60 C + 60 G = 120 pyrimidines

300 total bases - 120 pyrimidine bases = 180 purine bases.

180/2 = 90 equal bases of Adenine and Thymine. Hence, Thymine bases will be 90.

3 0

3 years ago

A student determines the density of an element to be 2.73 g/cm 3 . If the accepted value is 2.70 grams per cm 3 , what is the st

Brums [2.3K]

Answer:

Explanation:

percentage error = error x 100 / correct value

= (2.73 - 2.70) x100 / 2.70

= 1.11 %

The element is Aluminium whose density is 2.702 grams / cc

Boiling point of Aluminium = 2519⁰C .

8 0

3 years ago

Why melting and boiling points can be used as a way to check purity?

jekas [21]

Answer: Let's see why

Pure solid and liquid compounds possess sharp melting and boiling points. Therefore, melting and boiling points of a compound can be used as a criteria of purity. ... Sometimes during cooling minute quantity of the substance (solid which is being purified) is added to the solution to facilitate the initial crystallisation.

Explanation:

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2 years ago

Which of the following is a physical model of the Sun? A. an equation that describes the Sun’s motion B. a chart that lists the

Bezzdna [24]

Answer:

It would be E. A small yellow ball that represents the Sun Reset Next i got the answer from somebody else

Explanation:

hope this helps :)

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2 years ago