What are the percent compositions of vanadium and lead? a metallurgist begins with 1,250 grams of vanadinite (pb5(vo4)3cl) and ends up with 135 grams of pure vanadium and 915 grams of pure lead. the percent composition of vanadium in the ore is , and the percent composition of lead is . options: 1. a. 10.8% b. 14.3% c. 14.8% d. 62.4% 2. a. 55.6% b. 73.2% c. 16.0% d. 23.8%

1. 10.8%

2. 73.2%

Explanation:

1) Data

i) Sample: 1,250 grams of vanadinite (Pb₅ (VO₄)₃Cl

ii) V = 135 g

iii) Pb = 915 g

iv) % V = ?

v) % Pb =?

2) Formula

% composition =( mass in grams of element / mass in grams of sample) × 100

3) Solution

i) Vanadium

% V = (mass of V / mass of sample) × 100 = (135 g/ 1,250 g) × 100

% V = 10.8 % ← answer

ii) Lead

% Pb = (mass of Pb / mass of sample) × 100 = (915 g / 1,250 g) × 100

% Pb = 73.2% ← answer

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.