Answer : The role of limiting reagent or reactant is important in a chemical reaction because it can help the chemist to predict that complete amount of reactant is consumed, as it is limiting the reaction, only required moles of products can get formed instead of the theoretical yield where the perfect amount is used.
In short, Limiting reactant in a chemical reaction is the substance that is totally consumed when the chemical reaction is found to be complete.
1. Answer is ₉₂²³⁵U<span>
<span>Since this is an alpha emission the atomic number
of the daughter nucleus decreases by 2 while mass number decreases by 4 compared to
parent atom. Since parent atom has 94 as atomic number the daughter atom should
have </span>94 - 2 = 92 as atomic number<span> <span>and </span></span>239 - 4 = 235 as mass
number. <span>
</span></span>₉₄²³⁹Pu → ₂⁴He + ₉₂²³⁵U<span>
2. </span><span>Answer is </span>₉₁²³⁴Pa<span>
</span><span>Since this is a beta emission, a neutron is
converted into a proton while emitting an electron. Hence atomic number
increases by 1 compared to mass number but mass number remains as same. Hence,
the </span>atomic number of the
daughter atom<span> <span>should be </span></span>90 + 1 = 91<span> <span>which belongs to </span></span>Pa<span>. But the </span>mass number is same
as 234.<span>
</span>₉₀²³⁴Th → ₋₁⁰e + ₉₁²³⁴Pa<span>
</span><span>
3.<span> <span>Answer is </span></span></span>₈¹⁸O<span>
</span><span>Since this is a positron emission, a proton is converted into a neutron
while emitting an positron. Hence atomic number decreases by 1 compared to mass
number but mass number remains as same. Hence, the </span>atomic number of the
daughter atom<span> should be </span>9- 1
= 8 <span>which belong to </span>O<span>. But the </span>mass
number is same as 18.<span>
</span>₉¹⁸F → ₊₁⁰e + ₈¹⁸O<span>
4. </span>Answer is ₈₀²⁰¹Hg<span>
</span><span>This is an </span><span>electron capture
decay. </span>A<span> proton is converted into a neutron by emitting
a gamma ray. In this process </span>mass number remains
as same<span> <span>as parent atom which is </span></span>201<span>, but the </span>atomic number is
decreased by 1<span> <span>than parent atom. Hence atomic number of
daughter nucleus is 81 -1 = </span></span>80 <span>which belongs to </span>Hg.<span>
</span><span>
</span>₈₁²⁰¹Tl + ₋₁⁰e → ₀⁰γ + ₈₀<span>²⁰¹Hg</span>
C. Sulfur and oxygen (non metals) forms a covalent bond while the magnesium (a metal) will react with both non metals to form an ionic bond
That depends. there are 2 possible answers.
H
C - C = C - H gives a different answer on the right than on the left.
One the left side, the second Carbon is attached to a double bond and has but one hydrogen attached to it.
The Carbon on the right of the double bond has 2
H
C- C = C - H
H
I'm not sure what you should put. It's one of those things that I would repeat my argument and submit it.
Answer:
1.244x10^23 molecules
Explanation:
From Avogadro's hypothesis, 1mole of any substance contains 6.02x10^23 molecules.
This means that 1mole of SiO2 contains 6.02x10^23 molecules
1mole of SiO2 = 28 + (2x16) =28 +32 = 60g
If 1 mole(i.e 60) of SiO2 contains 6.02x10^23 molecules,
Therefore, 12.40g of SiO2 will contain = (12.40 x 6.02x10^23) / 60 = 1.244x10^23 molecules
