This thermochemical equation needs to be balanced. Hence, option B is correct.
<h3>What is a balanced chemical equation?</h3>
A balanced equation contains the same number of each type of atom on both the left and right sides of the reaction arrow.
The balanced thermochemical equation is:
→ 
Hence, option B is correct.
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Answer:
181.82 g/cm3
Explanation:
density is mass / volume so it is 500 / 2.75=181.82 g/cm3
Explanation:
The problem basically wants you to find a way to convert between the number of atoms present in the sample and the number of moles they are equivalent to.
To convert between atoms and moles we use something called Avogadro's constant, which basically acts as the definition of a mole.
More specifically, in order to have one mole of an element you need
6.022 x 10^23 atoms of that element. You can thus use this number as a conversion factor to take you from atoms to moles or vice versa.
In your case, you will have
3.90 x 10^ 26 atoms Zn x 1 mole Zn ( Avogrado’s constant) / 6.022 x 10^23 atoms Zn
= 6.5 x 10^8 is the answer
Explanation:
A cup of mixtures of iron fillings, sand and salt is a mixture who constituents are in the same phase i.e solid.
To separate them out we use the physical properties of the substances.
- First spread out the mixture uniformly over a piece of paper or on the table.
- Pass a bar magnet over it.
- The iron fillings will become attracted to the magnet and separate from the mixture.
- then pour water into the mixture of sand and salt
- the salt will dissolve since sand is made up of quartz which are highly insoluble.
- separate the water solution. Evaporate to dryness and recover the salt.
- the sand is left behind and dried.
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