a sample of an unknown pure substance x is analyzed and found to contain 7.94 g of element e1, 9.06 g of…

a sample of an unknown pure substance x is analyzed and found to contain 7.94 g of element e1, 9.06 g of element e2, and no other elements. a similar analysis is made of three other substances that also only contain elements e1 and e2. the results are shown in the table below. decide whether each substance is a pure substance. if you dont have enough information to decide, choose cant decide.\n| substance | mass of e1 | mass of e2 | pure substance? |\n| ---- | ---- | ---- | ---- |\n| a | 14.6 g | 8.36 g | pure substance ( ) mixture ( ) cant decide ( ) |\n| b | 19.1 g | 18.9 g | pure substance ( ) mixture ( ) cant decide ( ) |\n| c | 12.5 g | 16.5 g | pure substance ( ) mixture ( ) cant decide ( ) |

a sample of an unknown pure substance x is analyzed and found to contain 7.94 g of element e1, 9.06 g of element e2, and no other elements. a similar analysis is made of three other substances that also only contain elements e1 and e2. the results are shown in the table below. decide whether each substance is a pure substance. if you dont have enough information to decide, choose cant decide.\n| substance | mass of e1 | mass of e2 | pure substance? |\n| ---- | ---- | ---- | ---- |\n| a | 14.6 g | 8.36 g | pure substance ( ) mixture ( ) cant decide ( ) |\n| b | 19.1 g | 18.9 g | pure substance ( ) mixture ( ) cant decide ( ) |\n| c | 12.5 g | 16.5 g | pure substance ( ) mixture ( ) cant decide ( ) |

Answer

Explanation:

Step1: Recall the law of definite proportions

In a pure substance, the ratio of the masses of its constituent elements is always the same. For a mixture, this ratio can vary.

Step2: Calculate the mass - ratio for each substance

For substance A: The ratio of mass of (E_1) to mass of (E_2) is (\frac{14.6}{8.36}\approx1.75) For substance B: The ratio of mass of (E_1) to mass of (E_2) is (\frac{19.1}{18.9}\approx1.01) For substance C: The ratio of mass of (E_1) to mass of (E_2) is (\frac{12.5}{16.5}\approx0.76) Since the mass - ratios of the elements in substances B and C are different from that in substance A, and the mass - ratio within each substance is not consistent with others, these are mixtures.

Answer:

A. mixture B. mixture C. mixture