Which chemical formula represents the hydroxide ion? H+ H3O+ H2O OH-
2 answers:
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<u>Answer </u>
Answer 1 : 28.9 g of CO is needed.
Answer 2 : Six moles of over Nine moles of
Answer 3 : Four over two fraction can be used for the mole ratio to determine the mass of Fe from a known mass of .
Answer 4 : Mass of = (150 × 3 × 31.998) ÷ (232.29 × 1) grams
Answer 5 : 8.4 moles of sodium cyanide (NaCN) would be needed.
<u>Solution </u>
Solution 1 : Given,
Given mass of = 55 g
Molar mass of = 159.69 g/mole
Molar mass of CO = 28.01 g/mole
Moles of =
=
= 0.344 moles
Balanced chemical reaction is,
From the given reaction, we conclude that
1 mole of gives → 3 moles of CO
0.344 moles of gives → 3 × 0.344 moles of CO
= 1.032 moles
Mass of CO = Number of moles of CO × Molar mass of CO
= 1.032 × 28.01
= 28.90 g
Solution 2 : The balanced chemical reaction is,
From the given reaction, we conclude that the Six moles of over Nine moles of
is the correct option.
Solution 3 : The balanced chemical reaction is,
From the given balanced reaction, we conclude that Four over two fraction can be used for the mole ratio to determine the mass of Fe from a known mass of .
Solution 4 : Given,
Given mass of = 150 g
Molar mass of = 232.29 g/mole
Molar mass of = 31.998 g/mole
Moles of =
=
The balanced chemical equation is,
From the given balanced equation, we conclude that
1 mole of gives → 3 moles of
of
gives →
of
Mass of = Number of moles of
× Molar mass of
=
Therefore, the mass of = (150 × 3 × 31.998) ÷ (232.29 × 1) grams
Solution 5 : Given,
Number of moles of = 4.2 moles
Balanced chemical equation is,
From the given chemical reaction, we conclude that
1 mole of obtained from 2 moles of NaCN
4.2 moles of obtained → 2 × 4.2 moles of NaCN
Therefore,
The moles of NaCN needed = 2 × 4.2 = 8.4 moles
Answer: 17 years
Explanation:
Expression for rate law for first order kinetics for radioactive substance is given by:
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
a) for completion of half life:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
b) for 8900 g of the mass of the sample to reach 7700 grams
Thus it will take 17 years