For which substance is the mass distribution of elements consistent with the quantitative composition of potassium hydroxide?

Analysis:

Potassium hydroxide (KOH) consists of potassium (K), oxygen (O), and hydrogen (H). The atomic masses are approximately: K = 39.1, O = 16.0, H = 1.0. Therefore, the molar mass of KOH is approximately 39.1 + 16.0 + 1.0 = 56.1 g/mol.

The mass percentages are:

• K: (39.1 / 56.1) * 100% ≈ 69.7%
• O: (16.0 / 56.1) * 100% ≈ 28.5%
• H: (1.0 / 56.1) * 100% ≈ 1.8%

Now let's examine the pie charts:

• Chart 1: Approximately 70% (K), 28.5% (O), 1.5% (H). This matches our calculation for KOH.
• Chart 2: Approximately 43% (K), 54% (O), 3.5% (H). This does not match KOH.
• Chart 3: Approximately 54% (K), 42% (O), 3% (H). This does not match KOH.
• Chart 4: Approximately 53% (K), 5% (O), 42% (H). This does not match KOH.

Therefore, the first diagram corresponds to potassium hydroxide.

Answer: 1