基于鼹鼠概念的问题
印度哲学家 Maharishi kanad 假设,如果将一个物质分成更小的部分,它就会有更小的部分。但是,当事情不再可以进一步划分时,将会有一个点,那个最小的部分被称为 Parmanu。到18世纪末,科学家们意识到有元素和分子,元素的组合形成一个分子。让我们详细了解原子和分子,
什么是原子?
最基本的或物质的组成部分是原子。原子非常小,当数以百万计的原子结合在一起时,就得到了很小的一块物质。原子的半径以纳米为单位。原子和元素的名称现在由 IUPAC(国际纯化学和应用化学联合会)给出。大多数情况下,原子名称的符号是大写的第一个字母,如果使用了2个字母,则另一个字母是小写字母。例如,氧原子表示为 O,铝表示为 Al,等等。
什么是原子质量?
道尔顿给出了原子质量的概念。根据道尔顿的说法,每个元素都有一定的质量,称为原子质量。由于原子质量的引入可以解释恒定比例定律,因此科学家决定确定质量。原子的绝对质量很难找到,因此引入了原子的相对质量。原子质量的单位是“u”,之前是“amu”。因此,原子质量可以定义为以原子质量单位(amu)测量的任何元素的原子平均质量。由于原子质量表示原子的大小,因此它是原子核(质子和中子)的质量。
分子质量和摩尔的概念
原子质量的概念已在上一节中讨论过。这个概念也可以扩展到分子。物质的分子质量是分子内存在的所有单个原子的原子质量的总和。了解“鼹鼠”一词背后的概念。让我们通过下面提到的方程式来考虑化学反应。
2H 2 + O 2 ⇒ H 2 O
上述反应表明:
- 两个氢分子与一个氧分子结合。
- 4u 的氢气与 32u 的氧气结合生成 36u 的水。
可以推断,物质的数量可以用分子的质量或数量来表征。可以看出,在化学反应中,用原子数和分子数的形式来表示比较方便。 “鼹鼠”是为这项工作引入的单位。
The number of particles present in 1 mole of any substance is fixed with a value of 6.022 × 1023. This number is called avogadro number. The mass of 1 mole of a substance is equal to it’s molecular mass in grams.
示例问题
问题 1:求 H 2 O 的分子质量。
回答:
It is known that, the molecular mass of a substance is the sum of the atomic masses of all the individual atoms present inside the molecule.
Molecular Mass of H = 1u
Molecular Mass of O = 16u
Molecular Mass of H2O = 2(Molecular Mass of H) + Molecular Mass of O
⇒ Molecular Mass of H2O = 2(1) + (16)
⇒ Molecular Mass of H2O = 18u
问题 2:求 H 2 SO 4的分子质量。
回答:
It is known that, the molecular mass of a substance is the sum of the atomic masses of all the individual atoms present inside the molecule.
Molecular Mass of H = 1u
Molecular Mass of O = 16u
Molecular Mass of S = 32u
Molecular Mass of H2SO4 = 2(Molecular Mass of H) + Molecular Mass of S + 4(Molecular Mass of O)
⇒ Molecular Mass of H2SO4 = 2(1) + (32) + 4(16)
⇒ Molecular Mass of H2SO4 = 2 + 32 + 64
⇒ Molecular Mass of H2SO4 = 98u
问题 3:计算 0.5 摩尔 H 2 O 2的质量。
回答:
It is known that, the molecular mass of a substance is the sum of the atomic masses of all the individual atoms present inside the molecule.
Molecular Mass of H = 1u
Molecular Mass of O = 16u
Molecular Mass of H2O2 = 2(Molecular Mass of H) + 2(Molecular Mass of O)
⇒ Molecular Mass of H2O2 = 2(1) + 2(16)
⇒ Molecular Mass of H2O2 = 34u
So, the mass of 1 mole of H2O2 is 34g.
Thus, 0.5 mole of H2O2 will be 17g.
问题 4:计算 2 摩尔 N 2的质量。
回答:
It is known that,
Molecular Mass of N = 14u
Thus, molar mass of N2 will be 28g.
Mass of 2 moles N2 = 2 × 28
Mass of 2 moles N2 is 56g.
问题 5:计算 0.5 摩尔 HSO 4的质量。
回答:
It is known that, the molecular mass of a substance is the sum of the atomic masses of all the individual atoms present inside the molecule.
Molecular Mass of H = 1u
Molecular Mass of O = 16u
Molecular Mass of S = 32u
Molecular Mass of HSO4 = Molecular Mass of H + Molecular Mass of S + 4(Molecular Mass of O)
⇒ Molecular Mass of HSO4 = 1 + (32) + 4(16)
⇒ Molecular Mass of HSO4 = 1 + 32 + 64
⇒ Molecular Mass of HSO4 = 97u
So, the mass of 1 mole of HSO4 is 97g.
Thus, 0.5 mole of HSO4 will be 48.5g.
问题 6:求 8g O 2中的原子数。
回答:
It is known that,
Molecular Mass of O = 16u
Thus, molar mass of O will be 16g.
Number of moles = Given Mass/Molar Mass
= (8)(32)
= 1/4
= 0.25 moles
Number of Atoms in 0.25 moles = 0.25 × 6.022 × 1023
⇒ Number of Atoms in 0.25 moles = 1.5 × 1023
问题 7:求 46g Na 中的原子数。
回答:
It is known that,
Molecular Mass of Na = 23u
Thus, molar mass of O will be 23g.
Number of moles = Given Mass / Molar Mass
= (46)(23)
= 2 moles
Number of Atoms in 2 moles = 2 × 6.022 × 1023
⇒ Number of Atoms in 0.25 moles = 12.044 × 1023 atoms.
问题8:C 2 H 5 OH 的分子量是多少。在将分子分解成原子时进行解释。
解决方案:
As it is clear that there are three different types of atoms involved in the molecule C2H5OH. They are carbon, hydrogen, and oxygen.
Molecular mass of C = 12u
The molecular mass of O = 16u
The molecular mass of H = 1u
2 atoms of C = 12 × 2 = 24u
6 atoms of H = 1 × 6 = 6u
1 atom of O = 16 × 1 = 16u
Molecular mass of C2H5OH = 24 + 6 + 16 = 46u
问题9:O 2和2O 有什么区别?
回答:
The difference between O2 and 2O is that the former is a molecule consisting of 2 atoms of oxygen while the latter is not a molecule, they are two separate oxygen atoms. O2 is a stable molecule and is present in the air, on the other hand, 2O is unstable and is ready to combine with other atoms like hydrogen.
问题 10:在水中,氢气与氧气的质量比为 1:8。找出 5g 氢气所需的氧气质量?
解决方案:
The ratio of H:O by mass = 1:8
Now, equating the actual masses with the ratios,
1/8 = 5/y
Here, y is the unknown mass of oxygen.
1 × y = 8 × 5
y = 40g
Therefore, 40g of oxygen is required for 5g of hydrogen.