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xenn [34]
4 years ago
11

When did life first appear in earths oceans?

Chemistry
2 answers:
xz_007 [3.2K]4 years ago
7 0
Same time Life Appeared on Earth.
Klio2033 [76]4 years ago
6 0
Wasn't it like 2017 years ago?
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What type of a reaction takes place when atoms or molecules rearrange to form new substances
GREYUIT [131]
A chemical reaction happens when the atoms or molecules rearrange to form a new substance


6 0
4 years ago
Read 2 more answers
Anhydrous copper sulphate can be used in a test for water. What two things will happen when water is added to anhydrous copper s
Misha Larkins [42]

Answer:

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3 0
2 years ago
What happens to the electronegativity as you go from Lithium to Francium?<br> Why?
Y_Kistochka [10]

Answer:

Electronegativity in group 1 decreases as we go from Lithium to Francium.

Explanation:

Electronegativity is defined as the tendency of an element to attract an electron pair towards itself.

In a group generally this tendency decreases from top to bottom as the size of the atom increases and hence the positive nucleus get far from the outer orbital.

In the same way group 1 elements i.e. from Lithium to Francium electronegativity decreases.

8 0
3 years ago
Can you help me with this with a solution
LuckyWell [14K]

The complete table is inserted.

A table is given,

Formulas used:

pH=  -log(H⁺)

pOH=  -log(OH⁻)

pH+ pOH=14

Calculations:

For A: (H⁺)=2×10⁻⁸M

Using the pH formula:

pH=  -log(H⁺)=-log(2×10⁻⁸)=7.69

pOH=14 - 7.69=6.3

Calculating OH concentration,

pOH=  -log(OH⁻)

6.3= -log(OH⁻)

(OH⁻)=5.011×10⁻⁷M

Hence, the nature of A is basic.

Similarily,

For B,

(OH⁻)=1×10⁻⁷

Using the pH formula:

pOH=  -log(OH⁻)= -log(1×10⁻⁷)=7

pH=14-7=7

Calculating H concentration,

pH=  -log(H⁺)

7= -log(H⁺)

(H⁺)=1×10⁻⁷M

Hence, the nature of B is neutral.

Similarily,

For C,

pH=12.3

Using the pH formula:

pOH=14-12.3=1.7

Calculating H concentration,

pH=  -log(H⁺)

12.3= -log(H⁺)

(H⁺)=5.011×10⁻¹³M

Calculating OH concentration,

pOH=  -log(OH⁻)

1.7= -log(OH⁻)

(OH⁻)=1.99×10⁻²M

Hence, the nature of C is Basic.

Similarily,

For D,

pOH=6.8

Using the pH formula:

pH=14-6.8=7.2

Calculating H concentration,

pH=  -log(H⁺)

7.2= -log(H⁺)

(H⁺)=6.309×10⁻⁸M

Calculating OH concentration,

pOH=  -log(OH⁻)

6.8= -log(OH⁻)

(OH⁻)=1.58×10⁻⁷M

Hence, the nature of D is basic.

Learn more about the acid and bases here:

brainly.com/question/16189013

#SPJ10

3 0
2 years ago
Wich tools are appropriate to determine the densety of an irregular-shaped object ?
Svetach [21]

Answer:

The most accurate way to determine an object's volume, especially in the case of an irregularly shaped object, is to immerse it in water and measure the amount of water it displaces. A graduated cylinder large enough to hold both the object and enough water to fully immerse it is the best tool for this job.

5 0
4 years ago
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