Li2O(s)+H2O(g)→2LiOH(s) How many grams of Li2O must be carried on board to remove 70.0 kg of water?
What is the answer
Lithium oxide is used aboard the space shuttle to remove water from the atmosphere according to the equation

We need 116.1 kg of Li2O

Explanation:

Step 1: Data given

MAss of water = 70 kg = 70000 grams

Molar mass H2O = 18.02 g/mol

Molar mass of Li2O = 29.88 g/mol

Step 2: the balanced equation

Li2O(s)+H2O(g)→2LiOH(s)

Step 3: Calculate moles H2O

Moles H2O = mass H2O / molar mass H2O

Moles H2O = 70000 grams / 18.02 g/mol

Moles H2O = 3884.6 moles

Step 4: Calculate moles Li2O

For 1 mol Li2O we need 1 mol H2O to produce 2 moles LiOH

For 3884.6 moles H2O we need 3884.6 moles Li2O

Step 5: Calculate mass Li2O

MAss Li2O = moles * molar mass

MAss Li2O = 3884.6 moles *29.88g/mol

Mass Li2O = 116071.8 grams = 116.1 kg

We need 116.1 kg of Li2O

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.

there are two significant figures.