Explanation:
At room temperature, resistivity of tungsten is 
and the resistivity of aluminium is 
.
Temperature coefficient of aluminium (
) = 
and, 
= 
T = 
= 
So, at aluminium has resistivity which is three times the resistivity of tungsten at room temperature.
Answer:
Explanation:
We are asked to convert an amount in grams to moles. To do this, we use the molar mass. This is the number of grams in one mole of a substance. It is the same value numerically as the atomic mass on the Periodic Table, however the units are grams per mole, not atomic mass units.
Look up the molar masses for the individual elements.
- Sodium (Na): 22.9897693 g/mol
- Oxygen (O): 15.999 g/mol
Look back at the formula: Na₂O. Notice there is a subscript of 2 after sodium. This means there are 2 atoms of sodium in every molecule, so we have to multiply sodium's molar mass by 2 before adding oxygen's.
- Na₂O: 2(22.9897693 g/mol)+ 15.999 g/mol = 61.9785386 g/mol
Set up a ratio using the molar mass.
Multiply by the given number of grams.
Flip the ratio so the grams of sodium oxide can cancel each other out.
The original measurement of grams given has 3 significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place.
The 4 in the thousandth place tells us to leave the 8.
There are <u>2.48 moles of sodium oxide</u> in 154 grams, so choice A is correct.
Answer:
Q8) True
Q9) First ionization energy
Q10) Metal oxides
Explanation:
A common property of group one elements (alkali metals) is their combination with water to form basic solutions. E.g 2K(s)+2H2O(l)→2KOH(aq)+H2(g).
The distance of the outermost electron in the atom from the nucleus is inversely related to the first ionization energy. As the distance between the outermost electron and the nucleus in group 17 elements gets larger, the corresponding first ionization energies of elements in the group gets smaller.
Group 1 elements can combine with oxygen to give metal oxides. E.g 4K + O2 --> 2 K2O
It is known as the melting point
Explanation:
The temperature of the molten iron remained constant at 2750°C because of the heat absorbed to effect the phase change and not to change the temperature.
The heat of vaporization is a latent or hidden heat absorbed by substances that causes a phase change from liquid to gas.
- In essence, the heat is used to break intermolecular bonds between the particles of the melted vat.
- If enough heat is no supplied the molten vat will not boil off and become vapor.
- In transitioning from liquid to gas, heat is absorbed by a body to effect the phase change.
- When the body acquires enough heat, the particles are able to break off and boil.
- At the 2750°C mark, this is what is happening.
learn more:
Specific heat brainly.com/question/7210400
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