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Crank
3 years ago
9

Which of the following is NOT a sign of a chemical reaction:

Chemistry
2 answers:
Sergeeva-Olga [200]3 years ago
7 0
The answer is B. Precipitation
Liono4ka [1.6K]3 years ago
3 0
I think it’s B. I apologize if I was incorrect.
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If 650. grams of C6H12O6 (FW 180.16) reacts with 650. grams of O2 (FW 32.00) in cellular respiration: C6H12O6 6 O2 --> 6 CO2
cestrela7 [59]

Answer:

O2 is limiting reactant

Explanation:

To find the limiting reactant we need to convert the mass of each reactant to the moles using the formula weight. And, as 1 mole of C6H12O6 reacts with 6 moles of O2, we can know wich reactant will be over first (Limiting reactant) as follows:

<em>Moles C6H12O6:</em>

650g * (1mol/180.16g) = 3.608 moles C6H12O6

<em>Moles O2:</em>

650g * (1mol/32g) = 20.31 moles O2

Now, for a complete reaction of 3.608 moles of C6H12O6 are required:

3.608 moles C6H12O6 * (6mol O2 / 1mol C6H12O6) = 21.65 moles O2

As there are just 20.31 moles of O2,

<h3>O2 is limiting reactant</h3>
4 0
2 years ago
How many acidic H+ ion is given by H3BO3 in aqueous solution?? ...?
notka56 [123]
Boric acid, H3BO3, in aqueous solution would only give out one H+ ion. As it is also produce OH ion and by hydrolysis it produces one proton. <span>All the boron compounds (BX3) are having only 6 valence electrons in it and should follow the octet rule by taking another electron.</span>
 
B(OH)3 + 2 H2O → B(OH)4− + H3O
7 0
2 years ago
How does the highly reactive nature chlorine contribute to the creation of ozone holes in the upper atmosphere?
liberstina [14]
Chlorine is a halogen and is very reactive and unstable. If released in an elemental form (Cl2), it would react with other substances immediately. However, <span>chlorofluorocarbons (CFCs) which contain chlorine are unreactive and when released they eventually end up in the upper atmosphere still "intact". In the upper atmosphere, sunlight is more intense and is able to break apart CFC, releasing the highly reactive chlorine which in turns destroys ozone which is more abundant in the upper atmosphere (stratosphere). </span>
6 0
3 years ago
Three 5-l flasks, fixed with pressure gauges and small valves, each contains 4 g of gas at 273 k. flask a contains h2, flask b c
Varvara68 [4.7K]
First, please check the missing part in your question in the attachment.
a) So first, the Rank of pressure:
according to this formula PV = nRT and when n = m/Mw
PV = m/Mw * R*T
when we have the same mass m and the same V volume so P will proportional with the mole weight M as when the M is smaller the pressure will be greater 
when Mw of H2(A) = 2 g / Mw of He (B) = 4 g and Mw of CH4(C) = 16 g
∴ Pressure :
 (A) > (B) > (c)

B) The rank of average molecular kinetic energy:
when K = 3/2 KB T
when K is the average kinetic energy per molecule of gas 
and KB is Boltzmann's constant
and T is the temperature (K)
So from this equation, we can know that K only depends on T value, and when we have the T constant here for A, B, and C So the rank of K will be like the following:
∴ A = B = C
C) the rank of diffusion rate after the valve is opened:
according to this formula:
R2/R1 = √M1/M2
from this equation, we can see that diffusion is proportional to the reciprocal of the molecular mass M so,
when Mw H2 (A) = 2 g & Mw He(B) = 4 g & CH4 (C) = 16 g
∴ the rank of diffusion:
A > B > C

D) The rank of the Total kinetic energy of the molecules:
when we have the Mw different so it will make the no.of molecules differs as when the Mw is low the no.of molecules will be hight, and when the average molecular kinetic energy equals. so the total kinetic energy will depend on no. of molecules 
∵ Mw A < Mw B < Mw C 
∴no .of molecules of A > B >C
∴ the rank of total kinetic energy is:
A > B > C

e) the rank of density:

when ρ = m/ v 
and m is the mass & v is the volume and we have both is the same for A, B, and C
so the density also will be the same, ∴ the rank of the density is:
A = B = C

F) the rank of the collision frequency:
as the no.of molecules increase the collision frequency increase and depend also on the velocity and it's here the same.
∴ Collision frequency will only depend on the no.of molecules
we have no.of molecules of A > B > C as Mw A < B < C 
∴the rank of the collision frequency is:
A > B > C 

 



7 0
3 years ago
What is true about elements that are in the same column group or family
shusha [124]

The given question is incomplete. The complete question is:

Which is true of Elements on a periodic table in the same group (family)?

A; Elements in the same family have similar chemical properties because they have the same number of electron shells.

B; Elements in the same family have similar chemical properties because they have the same number of valence electrons.

C; Elements in the same family have few similar properties as they have different numbers of electron shells.

D; Elements in the same family are always the same type of Elements and have the same number of protons.

Answer: B; Elements in the same family have similar chemical properties because they have the same number of valence electrons.

Explanation:

Elements are distributed in groups and periods in a periodic table.

Elements that belong to same groups will show similar chemical properties because they have same number of valence electrons. The chemical reactivity of elements is governed by the valence electrons present in the element.

Example: Flourine, chlorine and bromine are elements which belong to Group 17. They have 9, 17 and 35 electrons respectively and contain 7 valence electrons each and need one electron to complete their octet.

3 0
2 years ago
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