Rust is formed by the interaction of iron and oxygen. when rust formed on an iron nail with a mass of 100 g, the mass of the rusted nail was 143g. what mass of oxygen gas most likely reacted with the iron nail? a) 43g b) 50g c) 100g d) 243g

The correct option is A.

Explanation: Moles of Iron nail can be calculated by using the formula:

      ...(1)

Given mass of iron nail = 100 g

Molar mass of iron = 56 g/mol

Number of moles of iron nail = 1.79 moles

The chemical equation for the formation of rust if given by:

By Stoichiometry of the reaction,

4 moles of iron reacts with 3 moles of oxygen gas to produce 2 moles of rust.

So, 1.79 moles of iron will react with = = 1.3425 moles of oxygen gas.

For oxygen gas,

Molar mass = 32 g/mol

Mass of oxygen can be calculated by using equation 1, we get

Mass of oxygen gas = 43 grams

Hence, the correct option is a.

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.

catya your not at all which answer i've seen you do this on another question!