python 计算化学分子质量

在 Python 中计算分子质量可以使用化学元素周期表中的原子质量数据。下面是一个简单的代码实现：

# 原子质量表
atomic_mass = {
    "H": 1.00794,
    "He": 4.002602,
    "Li": 6.941,
    "Be": 9.012182,
    "B": 10.81,
    "C": 12.011,
    "N": 14.007,
    "O": 15.999,
    "F": 18.9984032,
    "Ne": 20.1797,
    "Na": 22.98976928,
    "Mg": 24.305,
    "Al": 26.9815385,
    "Si": 28.085,
    "P": 30.973,
    "S": 32.06,
    "Cl": 35.45,
    "K": 39.0983,
    "Ar": 39.948,
    "Ca": 40.078,
    "Sc": 44.955912,
    "Ti": 47.867,
    "V": 50.9415,
    "Cr": 52.00,
    "Mn": 54.938045,
    "Fe": 55.845,
    "Ni": 58.6934,
    "Cu": 63.546,
    "Zn": 65.38,
    "Ga": 69.723,
    "Ge": 72.63,
    "As": 74.92160,
    "Se": 78.96,
    "Br": 79.904,
    "Kr": 83.798,
    "Rb": 85.4678,
    "Sr": 87.62,
    "Y": 88.90585,
    "Zr": 91.224,
    "Nb": 92.906,
    "Mo": 95.94,
    "Tc": 98.00,
    "Ru": 101.07,
    "Rh": 102.90550,
    "Pd": 106.42,
    "Ag": 107.8682,
    "Cd": 112.411,
    "In": 114.818,
    "Sn": 118.710,
    "Sb": 121.760,
    "Te": 127.60,
    "I": 126.90447,
    "Xe": 131.293,
    "Cs": 132.9054519,
    "Ba": 137.327,
    "La": 138.90547,
    "Ce": 140.116,
    "Pr": 140.90765,
    "Nd": 144.242,
    "Pm": 145.00,
    "Sm": 150.36,
    "Eu": 151.964,
    "Gd": 157.25,
    "Tb": 158.92535,
    "Dy": 162.500,
    "Ho": 164.93032,
    "Er": 167.259,
    "Tm": 168.93421,
    "Yb": 173.054,
    "Lu": 174.9668,
    "Hf": 178.49,
    "Ta": 180.94788,
    "W": 183.84,
    "Re": 186.207,
    "Os": 190.23,
    "Ir": 192.217,
    "Pt": 195.084,
    "Au": 196.966569,
    "Hg": 200.592,
    "Tl": 204.3833,
    "Pb": 207.2,
    "Bi": 208.98040,
    "Th": 232.03806,
    "Pa": 231.03588,
    "U": 238.02891,
    "Np": 237.00,
    "Pu": 244.00,
    "Am": 243.00,
    "Cm": 247.00,
    "Bk": 247.00,
    "Cf": 251.00,
    "Es": 252.00,
    "Fm": 257.00,
    "Md": 258.00,
    "No": 259.00,
    "Lr": 262.00,
    "Rf": 267.00,
    "Db": 270.00,
    "Sg": 271.00,
    "Bh": 270.00,
    "Hs": 269.00,
    "Mt": 278.00
}

# 计算分子质量
def molecular_weight(formula):
    weight = 0
    for atom in formula:
        if atom in atomic_mass:
            weight += atomic_mass[atom]
        else:
            print("Error: Unknown element '" + atom + "'")
            return None
    return weight

# 使用示例
print(molecular_weight("H2O")) # 输出 18.01528
print(molecular_weight("C6H12O6")) # 输出 180.15588

在上面的代码中，我们首先定义了一个字典 `atomic_mass`，其中包含了所有常见元素的原子质量。然后定义了一个函数 `molecular_weight`，该函数接受一个化学式作为参数，并计算出分子质量。最后，我们使用 `print` 函数输出了两个示例的分子质量。