百分比成分公式

百分比成分是指一种元素的量与总量乘以100的比值。百分比成分公式中使用的量通常以克为单位。它们在化学中的应用可以找到化合物中元素的百分比组成。它还有助于该化合物的化学分析。化合物被定义为两种或多种元素的混合物。

元素的百分比组成由下式给出：

$\frac{Mass\ of\ an\ element}{Total\ mass\ of\ a\ compound} \times 100$

要么

% C = gE/gC

Where,

gE is the mass of an element E in grams

gC is the mass of the compound C in grams

元素周期表中元素的质量通常以克每摩尔 (g/mol) 来描述。

例如，

求化合物 ABC 中元素 A 的组成百分比

如果 A 的质量 = 30

B = 40

C = 50

要找到元素的百分比组成，我们首先需要找到元素的质量和化合物中每种元素的总质量。

元素的质量 A = 30

对于总质量，我们需要添加元素 A、B 和 C 的质量。

总质量 = A 质量 + B 质量 + C 质量

总质量 = 30 + 40 + 50

总质量 = 120

添加后，我们得到：

总质量 = 120

百分比构成 = 30/120 × 100

=1/4 × 100

= 25%

因此，化合物中元素 A 的组成百分比为 25%。

示例问题

问题 1：求化合物 Ca(OH) ₂中钙 (Ca) 的百分比组成？

解决方案：

The above compound has three elements calcium, oxygen, and hydrogen. We need to divide the mass of calcium with the total mass of the compound.

Molar mass of Calcium = 40 g/mol

Molar mass of Oxygen = 16 g/mol

Molar mass of hydrogen = 2 g/mol

Total mass = mass of calcium + mass of oxygen + mass of hydrogen

Total mass = 40 + 2×16 + 2×1

Total mass = 40 + 32 + 2

Total mass = 74 g/mol

Percent composition of Calcium = $\frac{mass\ of\ calcium}{total\ mass} \times 100$

Percent composition of Calcium = $\frac{40}{74} \times 100$

Percent composition of Calcium = 54%

问题 2：求化合物 Ca(OH) ₂中氧 (O) 的百分比组成？

解决方案：

The above compound has three elements calcium, oxygen, and hydrogen. We need to divide the mass of Oxygen with the total mass of the compound.

Molar mass of Calcium = 40 g/mol

Molar mass of Oxygen = 16 g/mol

Molar mass of hydrogen = 2 g/mol

Total mass = mass of calcium + mass of oxygen + mass of hydrogen

Total mass = 40 + 2×16 + 2×1

Total mass = 40 + 32 + 2

Total mass = 74 g/mol

Percent composition of oxygen = $\frac{mass\ of\ calcium}{total\ mass} \times 100$

Percent composition of oxygen = $\frac{32}{74} \times 100$

Percent composition of oxygen = 43.24%

It is because there are two atoms of oxygen in the compound.  

问题 3：求化合物 Ca(Cl) ₂中钙 (Ca) 的百分比组成？

解决方案：

The above compound has two elements calcium and chloride. We need to divide the mass of calcium with the total mass of the compound.

Molar mass of Calcium = 40 g/mol

Molar mass of chloride = 35.5 g/mol

Total mass = mass of calcium + mass of chloride

Total mass = 40 + 2×35.5

Total mass = 40 + 71

Total mass = 111 g/mol

Percent composition of oxygen = $\frac{mass\ of\ calcium}{total\ mass} \times 100$

Percent composition of oxygen = $\frac{40}{111} \times 100$

Percent composition of oxygen = 36.03%

问题 4：求化合物 Ca(Cl) ₂中氯 (Cl) 的百分比组成？

解决方案：

The above compound has two elements calcium and chlorine. We need to divide the mass of chlorine by the total mass of the compound.

Molar mass of Calcium = 40 g/mol

Molar mass of chlorine = 35.5 g/mol

Total mass = mass of calcium + mass of chlorine

Total mass = 40 + 2×35.5

Total mass = 40 + 71

Total mass = 111 g/mol

Percent composition of chlorine = $\frac{mass\ of\ calcium}{total\ mass} \times 100$

Percent composition of chlorine = $\frac{71}{111} \times 100$

Percent composition of chlorine = 63.96%

问题 5：找出化合物 CaCO ₃中钙 (Ca) 的百分比组成？

解决方案：

The above compound has three elements calcium, carbon, and oxygen. We need to divide the mass of calcium with the total mass of the compound.

Molar mass of Calcium = 40 g/mol

Molar mass of carbon = 12 g/mol

Molar mass of oxygen = 16 g/mol

Total mass = mass of calcium + mass of carbon + mass of oxygen

Total mass = 40 + 12 + 3×16

Total mass = 40 + 12 + 48

Total mass = 100 g/mol

Percent composition of calcium = $\frac{mass\ of\ calcium}{total\ mass} \times 100$

Percent composition of calcium = $\frac{40}{100} \times 100$

Percent composition of calcium = 40%

问题 6：求化合物 CaCO ₃中碳 (C) 的百分比组成？

解决方案：

The above compound has three elements calcium, carbon, and oxygen. We need to divide the mass of carbon by the total mass of the compound.

Molar mass of Calcium = 40 g/mol

Molar mass of carbon = 12 g/mol

Molar mass of oxygen = 16 g/mol

Total mass = mass of calcium + mass of carbon + mass of oxygen

Total mass = 40 + 12 + 3×16

Total mass = 40 + 12 + 48

Total mass = 100 g/mol

Percent composition of carbon = $\frac{mass\ of\ calcium}{total\ mass} \times 100$

Percent composition of carbon = $\frac{12}{100} \times 100$

Percent composition of carbon = 12%

问题 7：求化合物 CaCO ₃中氧 (O) 的百分比组成？

解决方案：

The above compound has three elements calcium, carbon, and oxygen. We need to divide the mass of oxygen by the total mass of the compound.

Molar mass of Calcium = 40 g/mol

Molar mass of carbon = 12 g/mol

Molar mass of oxygen = 16 g/mol

Total mass = mass of calcium + mass of carbon + mass of oxygen

Total mass = 40 + 12 + 3×16

Total mass = 40 + 12 + 48

Total mass = 100 g/mol

Percent composition of oxygen = $\frac{mass\ of\ calcium}{total\ mass} \times 100$

Percent composition of oxygen = $\frac{48}{100} \times 100$

Percent composition of oxygen = 48%

The total percentage of each component in a substance is always 100%.