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zavuch27 [327]
3 years ago
13

Why do organisms evolve?

Chemistry
1 answer:
Mekhanik [1.2K]3 years ago
5 0

Answer:B

Explanation:

Natural Selection

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what is the trend for the size as you go from Be to Mg to Ca? does the atomic size increase, decrease, or remain the same? how w
lys-0071 [83]

Answer:

the size of Ca is the greatest ,then Mg is the greater on size than Be

Explanation:

if you make the  electron configuration for each of the elements, what  is the main  difference  u gonna see ?

Be 4   1s2/2s2

Mg 12 1s2 /2s2 2p6/3s2

Ca 20 1s2 /2s2 2p6/3s2 3p6 3d/4s2

see that all the elements are in the same group but are in different period

u gonna see the last electron valance shell in Ca are too far  from its nucleus but in  Be the last electrons are too close and more attracted to the atom's nucleus , so the size of Ca is the biggest then Mg then Be

4 0
4 years ago
What mass of HCl (in Kg) is required to create 8.80 Liters of hydrogen gas?
tiny-mole [99]
The important thing to notice here is that the reaction takes place at STP conditions, which are defined as a pressure of
100 kPa
and a temperature of
0
∘
C
.
Moreover, at STP one mole of any ideal gas occupies exactly
22.7 L
- this is known as the molar volume of a gas at STP.
Since all the gases are at the same conditions for pressure and temperature, the mole ratios become volume ratios.
To prove this, use the ideal gas law equation to write the number of moles of hydrogen gas and of chlorine gas as
P
V
=
n
R
T
⇒
n
=
P
V
R
T
For hydrogen, you would have
n
hydrogen
=
P
⋅
V
hydrogen
R
T
and for chlorine you have
n
chlorine
=
P
⋅
V
chlorine
R
T
Thus, the mole ratio between hydrogen and chlorine will be
n
hydrogen
n
chlorine
=
P
V
hydronge
R
T
⋅
R
T
P
⋅
V
chlorine
=
V
hydrogen
V
chlorine
The same principle applies to the mole ratio that exists between hydrogen and hydrogen chloride.
So, the balanced chemical equation for this reaction is
H
2(g]
+
Cl
2(g]
→
2
HCl
(g]
Notice that you have a
1
:
2
mole ratio between hydrogen gas and hydrogen chloride.
This means that the reaction will produce twice as many moles as you the number of moles of hydrogen gas that reacts.
Use the volume ratio to find what volume of hydrogen chloride will be produced by the reaction
4.9
L H
2
⋅
2
L HCl
1
L H
2
=
9.8 L HCl
Now use the molar volume to find how many moles you'd get in this volume of gas at STP
9.8
L HCl
⋅
1 mole HCl
22.7
L HCl
=
0.4317 moles HCl
Finally, use hydrogen chloride's molar mass to find how many grams would contain this many moles
0.4317
moles HCl
⋅
36.461 g
1
mole HCl
=
15.74 g
Rounded to two sig figs, the answer will be
m
HCl
=
16 g
3 0
3 years ago
12.1 g CoCl3 calculate the amount, in moles
elena-s [515]

Answer:

Number of moles of CoCl3 =  0.09 moles

Explanation:

Given data:

Mass of CoCl₃ = 12.1 g

Number of moles = ?

Solution:

First of all we will calculate the molar mass.

Molar mass of CoCl3 = 28.01 + (35.5×3)

Molar mass of CoCl3 = 28.01 + 106.5

Molar mass of CoCl3 = 134.51 g/mol

Number of moles of CoCl3 = mass / molar mass

Number of moles of CoCl3 = 12.1 g/134.51 g/mol

Number of moles of CoCl3 =  0.09 moles

4 0
4 years ago
!!Help!!Polysaccharides are healthier for the body than mono- or disaccharides are. What choices could you make to increase your
const2013 [10]

Answer:

We have to consume starch and cellulose in large amount in order to increase the consumption of polysaccharides which make our body healthier.

Explanation:

Starch is polysaccharide which is made up of many glucose molecules. it is mostly made in the body of plants and when we eat that plant this starch is transferred to our body and our body use it when it is needed while cellulose also made of hundred of glucose molecules but our body is unable to digest it because our body is unable to break the bonds between the monosaccharide of cellulose. It is good for humans due to the presence of high amount of fibers.

3 0
4 years ago
Which model is Bohr credited with developing? the nuclear model of the atom the orbital model of the atom the plum pudding model
yuradex [85]

Answer:

Orbital

Explanation:

He developed the Rutherford model, which was the orbital model.

3 0
3 years ago
Read 2 more answers
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