Just need help on these questions :) 1. _ is a positive ion and ___ is a negative ion.
2. Two or more substances mixed but not chemically combined are a _.
3. Acids solutions have pH values below ___.
4. A solution with a pH of 0 is very ___.
5. A solution with a pH of 7 is ___.
6. Pure water has a pH of __.
7. Basic solutions have pH values above__.

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? a. the balloons both rise. the cold balloon is larger than the warm balloon. b. the balloons rise at the same rate. both balloons are the same size. c. the warm balloon expands and rises. the cold balloon shrinks and sinks. d. the cold balloon expands and rises. the warm balloon shrinks and sinks.

Ase your answer to this question on the information below. hydrocarbons and fissionable nuclei are among the sources used for the production of energy in the united states. a chemical reaction produces much less energy than a nuclear reaction per mole of reactant. the balanced chemical equation below represents the reaction of one molecule of a hydrocarbon with two molecules of oxygen. chemical equation: ch4 + 2o2 → co2 + 2h2o + 1.48 × 10−18 jthe nuclear equation below represents one of the many possible reactions for one fissionable nucleus. in this equation, x represents a missing product. nuclear equation: write an isotopic notation for the missing product represented by x in the nuclear equation.

Which formula can be used to calculate the molar mass of ammonia (nh3)? molar mass of n + molar mass of h 3 × molar mass of n + molar mass of h molar mass of n + 3 × molar mass of h 3 × molar mass of n + 3 × molar mass of h