Answer:
C
Explanation:
The presence of mobile electrons explains the reason why there is conduction of electricity in the solid state. Electrons are the part of atoms that are majorly responsible for the different characteristics that substances exhibit.
A good example of the conduction of electricity can be seen in the case of 2 crystalline forms of carbon. While one of the allotropes could conduct electricity, the other allotrope cannot conduct electricity.
The two allotropes we are talking about here is graphite and diamond. While graphite could be used in a whole lot of electrolysis set up as an electrode, diamond does not found use in cases like this despite its crystalline structure. The reason for this is simple.
While diamond does not contain free mobile electron in its molecule, these free mobile electrons are present in a molecule of graphite. These free mobile electrons are the main reason why graphite can conduct electricity and diamond cannot even though they are both crystalline forms of carbon.
Answer:
1.85 g of hydrogen gas will form!
Explanation:
1. Write the balanced equation.
Zn
+
2HCl
→
ZnCl
2
+
H
2
2. Calculate the moles of
Zn
.
Moles of Zn
=
30.0
g Zn
×
1 mol Zn
65.38
g Zn
=
0.4589 mol Zn
3. Calculate the moles of
H
2
.
Moles of H
2
=
0.4589
mol Zn
×
2 mol H
2
1
mol Zn
=
0.9177 mol H
2
4. Calculate the mass of
H
2
.
Mass of H
2
=
0.9177
mol H
2
×
2.016 g H
2
1
mol H
2
=
1.85 g H
2
Potassium (K), Sodium(Na), Iron(Fe), Copper(Cu), Silver(Ag), Tin(Sn), Antimony(Sb), Tungsten(W), Gold(Au), Mercury(Hg), Lead(Pb)
Answer:
70%of 2000 = 1400
2000 tonnes of hematite contains 1400 tonnes iron oxide .
1400 tonnes of fe2O3
fe2O3 have molar mass 159.69
calculate moles = given mass/molar mass
moles = 1400000000/159.69
moles = 8766986
one mole contains = 112 g of fe
so 8766986 moles will contain = 112×8766986
= 981,902,432 grams of ferrous
which is nothing but equal to 981.90 tonnes of iron!!
Answer:
Explanation:
1 mole of any substance contains the same number of particles. The particles can vary (atoms, molecules, formula units), but there are always 6.022*10²³ particles. In this case, the particles are formula units of potassium nitrate or KNO₃.
Let's create a ratio.
Since we are trying to find the formula units in 0.250 moles, we multiply by that number.
The units of moles of potassium nitrate cancel.
The denominator of 1 can be ignored, so we can make a simple multiplication problem.
If we round to the nearest tenth, the 0 in the hundredth place tells us to leave the 5 in the tenth place.
0.250 moles of potassium nitrate is approximately equal to 1.5*10²³ formula units of potassium nitrate and choice B is correct.
