Strontium 90 (sr-90, a radioactive isotope of strontium, is present in the fallout resulting from nuclear explosions. it is especially hazardous to animal life, including humans, because, upon ingestion of contaminated food, it is absorbed into the bone structure. its half-life is 27 years. if the amount of sr-90 in a certain area is found to be four times the "safe" level, find how much time must elapse before the safe level is reached.

Aperfume bottle is dropped in the corner of a room. the odor of the perfume can be detected on the other side of the room. which statement best describes this observation?

To find the enthalpy of a reaction in the lab, you measured the of the reactants and the change during the reaction.

Activity two: just lemons, inc. production here's a one-batch sample of just lemons lemonade production. determine the percent yield and amount of leftover ingredients for lemonade production and place your answers in the data chart. hint: complete stoichiometry calculations for each ingredient to determine the theoretical yield. complete a limiting reactant-to-excess reactant calculation for both excess ingredients. water sugar lemon juice lemonade percent yield leftover ingredients 946.36 g 196.86 g 193.37 g 2050.25 g 89% just lemons lemonade recipe equation: 2 water + sugar + lemon juice = 4 lemonade mole conversion factors: 1 mole of water = 1 cup = 236.59 g 1 mole of sugar = 1 cup = 225 g 1 mole of lemon juice = 1 cup = 257.83 g 1 mole of lemonade = 1 cup = 719.42 g show your calculations below. analysis questions 1. based on taste observations only, which ingredients were in excess in the lemonade samples in activity one? in activity one the excess substances for each sample were the water and sugar. 2. based on the data in activity two, which excess ingredients are affecting the taste of the lemonade in the sample batch? 3. what can just lemons, inc. do during production to reduce the amount of excess ingredients and improve the taste of their lemonade? 4. try to reduce the amount of leftover ingredients by changing the amount of one, two, or all three starting ingredients. show your stoichiometric calculations below. 5. during factory inspection, just lemons, inc. discovered that a water valve to the lemonade mixing station was not functioning. once they repair it, more water will enter the mixing station. from what you know about the limiting and excess ingredients for current lemonade production, what advice would you give engineers about the upcoming increase in water?