4. Why do elements in the same family generally have similar properties?

1 answer:

7 0

Because they have the same number of electrons in the outer shell, they have the same reactivity (they all want to lose/gain a certain amount of electrons to have a full shell of 8), so they have the similar melting, boiling points etc because they all undergo very similar reactions to certain factors so have similar outcomes

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Question 6 pls I need help this is due in 2 minutes!!..

MAVERICK [17]

Answer:

Explanation:

7 0

3 years ago

Read 2 more answers

Which of these half-reactions represents reduction?

gogolik [260]

Answer: The half-reactions represents reduction are as follows.

$Cr_{2}O^{2-}_{7} \rightarrow Cr^{3+}$
$MnO^{-}_{4} \rightarrow Mn^{2+}$

Explanation:

A half-reaction where addition of electrons take place or a reaction where decrease in oxidation state of an element takes place is called reduction-half reaction.

For example, the oxidation state of Cr in $Cr_{2}O^{2-}_{7}$ is +6 which is getting converted into +3, that is, decrease in oxidation state is taking place as follows.

$Cr_{2}O^{2-}_{7} + 3 e^{-} \rightarrow Cr^{3+}$

Similarly, oxidation state of Mn in $MnO^{-}_{4}$ is +7 which is getting converted into +2, that is, decrease in oxidation state is taking place as follows.

$MnO^{2-}_{4} + 5 e^{-} \rightarrow Mn^{2+}$

Thus, we can conclude that half-reactions represents reduction are as follows.

$Cr_{2}O^{2-}_{7} \rightarrow Cr^{3+}$
$MnO^{-}_{4} \rightarrow Mn^{2+}$

3 0

3 years ago

Calculate concentration of methylene blue . Give answer in molarity. concentration in ppm=4.8

PSYCHO15rus [73]

Answer:

The molarity of methylene blue is 1.5 × 10⁻⁵ M

Explanation:

When we talk about aqueous solutions, 1 ppm means 1 mg of solute per liter of solution. We need to express this concentration in molarity, which is moles of solute per liter of solution. To convert mass to moles we need the molar mass of methylene blue(MB), which is 320 g/mol.

Then,

$\frac{4.8mgMB}{1Lsolution} .\frac{1gMB}{10^{3}mgMB } .\frac{1molMB}{320gMB} =1.5 \times 10^{-5} M$