# Mass density and volume relationship in chemical equations

### How do you calculate mass using density and volume? | Socratic Calculate volumes of gases consumed/produced in a reaction using gas in volume or mass, of gas consumed or produced in a chemical reaction. relationships of the reactants and products in chemical reactions (chemical equations). Mass, volume and density are three of an object's most basic properties. Although the formula used to calculate volume depends on its shape. This is the mole ratio between two factors in a chemical reaction found through the ratio of Density ($$\rho$$) is calculated as mass/volume.

### Stoichiometric Calculations: Amounts of Reactants and Products - Chemistry LibreTexts

Following is a picture outlining these ideas. Look across the same row and read the percent written. To find the percent mass of fat in the whole food, you could divide 3. The Lucky Copper Coin The penny should be called "the lucky copper coated coin. Afterthe US government started adding other cheaper metals to the mix. The penny, being only one cent, is literally not worth its weight in copper.

People could melt copper pennies and sell the copper for more than the pennies were worth. Afternickel was mixed with the more expensive copper. Afterthe penny was made of bronze. For one year,the penny had no copper in it due to the expense of the World War II. It was just zinc coated steel. The copper coats the outside of the penny while the inner portion is zinc. The percent composition of a penny may actually affect health, particularly the health of small children and pets. Since the newer pennies are made mainly of zinc instead of copper, they are a danger to a child's health if ingested.

Zinc is very susceptible to acid. If the thin copper coating is scratched and the hydrochloric acid present in the stomach comes into contact with the zinc core it could cause ulcers, anemia, kidney and liver damage, or even death in severe cases.

Of course, the more pennies swallowed, the more danger of an overdose of zinc. The more acidic the environment, the more zinc will be released in less time. In this kind of situation, time is of the essence. The faster the penny is removed, the less zinc is absorbed. Below is a picture of a scratched penny before and after it had been submerged in lemon juice.

As you can see, the copper is vastly unharmed by the lemon juice. That's why pennies made before with mainly copper except the penny are relatively safe to swallow.

Chances are they would pass through the digestive system naturally before any damage could be done. Yet, it is clear that the zinc was partially dissolved even though it was in the lemon juice for only a limited amount of time.

Summary Density and percent composition are important concepts in chemistry. Each have basic components as well as broad applications. Components of density are: An application of the concept of density is determining the volume of an irregular shape using a known mass and density.

Determining Percent Composition requires knowing the mass of entire object or molecule and the mass of its components. In the laboratory, density can be used to identify an element, while percent composition is used to determine the amount, by mass, of each element present in a chemical compound. Single displacement is when an element from on reactant switches with an element of the other to form two new reactants.

Double displacement is when two elements from on reactants switched with two elements of the other to form two new reactants. Acid- base reactions are when two reactants form salts and water.

Molar Mass Before applying stoichiometric factors to chemical equations, you need to understand molar mass. Molar mass is a useful chemical ratio between mass and moles. The atomic mass of each individual element as listed in the periodic table established this relationship for atoms or ions.

Since there is a ratio of 4: Variation in Stoichiometric Equations Almost every quantitative relationship can be converted into a ratio that can be useful in data analysis. This ratio can be useful in determining the volume of a solution, given the mass or useful in finding the mass given the volume. In the latter case, the inverse relationship would be used.

A percent mass states how many grams of a mixture are of a certain element or molecule. This is useful in determining mass of a desired substance in a molecule. If the total mass of the substance is 10 grams, what is the mass of carbon in the sample? How many moles of carbon are there? Given volume and molarity, it is possible to calculate mole or use moles and molarity to calculate volume.

## 3.9 Stoichiometric Calculations: Amounts of Reactants and Products

This is useful in chemical equations and dilutions. Example 7 How much 5 M stock solution is needed to prepare mL of 2 M solution? These ratios of molarity, density, and mass percent are useful in complex examples ahead. Determining Empirical Formulas An empirical formula can be determined through chemical stoichiometry by determining which elements are present in the molecule and in what ratio.

## Density and Percent Compositions

The ratio of elements is determined by comparing the number of moles of each element present. Combustion of Organic Molecules 1. What is the empirical formula of the organic molecule? The problem requires that you know that organic molecules consist of some combination of carbon, hydrogen, and oxygen elements.