In real-life situations, workers collect water samples in a lake or stream instead of using samples a and b. for this lab to work, sodium carbonate was added to make the water samples alkaline. in lakes and streams it is calcium carbonate (caco3) that causes alkalinity. calcium carbonate acts as a buffer, a substance that serves to resist small changes in acidity or alkalinity in a solution. when acid rain enters lake water, it can be neutralized by the bases present and thus the lake does not become too acidic. since the key ion is the hydroxide ion, the nature of the cation doesn't matter in this case. right now, pollution workers are measuring calcium carbonate in lakes and streams. if a worker studied two lakes and lake x had a greater ppm of calcium carbonate than lake z, which of the two lakes would be able to withstand a greater amount of acid rain? explain your answer.

Which of the following is true for the actual yield of a reaction? it is always calculated as a ratio. it is the yield from the excess reactant. it is the yield from the limiting reactant. it is always less than the theoretical yield.

Which of the following statements about hybrid orbitals is or are true? choose all that apply. choose all that apply. under sp2 hybridization, the large lobes point to the vertices of an equilateral triangle. after an atom undergoes sp hybridization there is one unhybridized p orbital on the atom. the angle between the large lobes of sp3 hybrids is 109.5∘

The last few miles of the marathon are the most difficult for heather, her hair plastered to her head, sweat clinging to her arms, and her legs already feeling as if they had nothing left, just dead weight. after grabbing a cup of ice water, she feels the ice cubes smash against her nose as she gulps some cool refreshment and keeps on running. in these last few miles, the breeze kicks up and she finally feels some coolness against her skin. drips of sweat, once clinging to her forehead, now spill down, and heather feels more pain as the sweat flows into her eyes.which of the following is the most likely reason why the ice struck heather’s nose when she took a drink? a) water can function as a solvent. b) water can store large amounts of heat. c) water can moderate temperatures through evaporative cooling. d) the density of water decreases when it freezes. e) water has a cohesive nature.sweat remained on heather’s forehead and arms because of the a) high salt content of sweat b) cohesive nature of water c) ability of water to moderate heat d) high evaporative cooling effect of water e) ability of water to act as a solvent