Answer:
He is wrong . Most accurate is Buret .
Explanation:
The number of significant figure denotes the level of accuracy of a measurement .
Beaker can measure liquid in mL upto significant figure of 2 . That means it can measure volume in terms of 10 , 20 , 30mL etc . It can not measure 25 mL
accurately . The last figure of 28 mL is read by guess in the question . So it is not an accurate measurement .
Similarly , graduated cylinder can measure liquid upto significant figure of 3 . That means it can measure volume in terms of 11 , 22 , 33 mL etc . It can not measure 25.5 mL accurately . The last figure of 28.3 mL is read by guess in the question . So it is less accurate measurement .
Similarly , buret can measure liquid upto significant figure of 4 . That means it can measure volume in terms of 11.2 , 22.3 , 33.5 mL etc . It can not measure 25.53 mL accurately . The last figure of 28.32 mL is read by guess in the question . So it is most accurate among all the three instrument because it can measure accurately mL upto one tenth of it .
We can predict formula of ionic compounds by:
- Take a look at where the elements are listed on the periodic table.
- The amount of electrons that an element would need to gain or lose in order to resemble an atom of a nearby noble gas is one of the similarities that atoms in the same column as one another (group) tend to display.
- Alkali metal group I ions have +1 charges.
- Alkaline earth metals (group 2 ions) have a +2 charge.
- Nonmetal group 6 ions have a charge of -2.
- Halides in group 7 have a -1 charge.
- The charges of the transition metals cannot be predicted in a straightforward manner.
- Check out a table of charges (valences) to see potential values. The +1, +2, and +3 charges are most frequently employed in beginning and general chemistry courses.
- Keep in mind that the positive ion is always stated first when writing an ionic compound's formula.
These are the few guidelines we can use to product formula.
Learn more about ionic compounds here:
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There are 7 signifigant figures in this number!