When a chemical change occurs . Need ASAP please someone
Select one:
a. atoms are rearranged
b. the law of conservation of mass is always obeyed
c. the chemical properties of new substances are different from the ones you started with
d. all of these

9. write the chemical equation for the following word equations. include symbols for physical states in the equation. a. solid zinc sulfide + oxygen gas -> solid zinc oxide + sulfur dioxide gas b. aqueous hydrochloric acid + aqueous barium hydroxide -> aqueous barium chloride + water

For a family dinner, jose’s mom baked a loaf of bread. during the meal, his grandmother commented, “this bread is so dense! ” what do you think his grandmother meant by the word dense? you have some ideas regarding density already, but this experiment will enrich your understanding of the relationship between mass, volume and the density of objects. when making measurements in this experiment we will be using si units, the international system of units. the purpose of using si units is to have the ability to communicate and compare data results with other experiments without having to make conversions. measurement symbol si unit length m meter mass kg kilogram volume l liters density kg/l kilograms per liter any calculations that are performed during this experiment will ultimately be reported in scientific notation. recall that scientific notation is extremely important when we have data that is extremely small or large. scientists rely on a standard form of communication to quickly make hypotheses and judgements based on data. what is the density of block a? a0kg/l what is the density of block b? a1kg/l what is the density of block c? a2kg/l what is the density of block d? a3kg/l what is the density of block e? a4kg/l which block is the densest? a5

Why do oxygen have a strong attractive force for electrons