Ud. analiza 1.5 kg de una muestra de agua contaminada con Cr+6 (Cromo hexavalente), causante de la muerte de peces en un lago y concluye que tiene
una concentración de 67 ppm. ¿Cuántos mg de Cr+6 (Cromo hexavalente) tiene
la muestra?

plants need sunlight, water, and carbon dioxide to make food. plants use the raw materials of water, nutrients they absorb from soil, and carbon dioxide to make sugars the plant can use. energy from the sun and chlorophyll are also needed.

acid rain does not usually kill trees directly. instead, it is more likely to weaken the trees by damaging their leaves, limiting the nutrients available to them, or poisoning them with toxic substances slowly released from the soil. the main atmospheric pollutants that affect trees are nitrates and sulphates.