What is the percent by mass of sodium in na2so4? total mass of element in compound molar mass of compound use %element x 100

Janel’s class studied properties of matter and how matter can change. janel decided she would do an experiment mixing baking soda and vinegar.question: describe the properties of baking soda and vinegar, and explain the changes that janel should see when she mixes the two types of matter. •first, identify the physical state of matter of baking soda. describe another property of baking soda. •next, identify the physical state of matter of vinegar. describe another property of vinegar. •then, explain what janel should see when she mixes the baking soda and vinegar. •describe the states of matter of the new materials that are formed. •explain how janel can be certain a change has occurred. me

Why does his teacher ask him to balance the equation by including the correct coefficient

Me i dont know what to do! the table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 10 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.