Jhjkjnkjnbnb hb jbhb hbh

Which of these would be caused by a chemical change? a) the formation of lava. b) sedimantary rock layering over time. c) metamorphic rock forming from igneous. d) metamorphic rock eroding to form sedimentary rock.

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)

In this problem, you will determine the biosynthetic cost of generating the amino acid serine from glucose used as food. the biosynthetic costs of all the amino acids are given in table 5.1, and now you will get a first-hand sense of how to obtain those values. visit the website and find the metabolic pathways for serine synthesis and glycolysis. the starting molecule of the serine synthesis pathway is an intermediate in glycolysis. how many molecules of glucose must be taken up to provide the carbon skeleton used to make serine? draw the biochemical pathway starting with glucose and ending in serine, labeling the energy-requiring and energy-generating steps. how many molecules of atp are consumed and created along the way? how many reducing equivalents of nadh and nadph are consumed or created along the way? in order to answer this question completely, you may need to consider a few other pathways as well. for example, it is likely that the displayed glycolysis pathway does not actually start with glucose. to get glucose 6-phosphate from glucose requires 1 atp. one of the steps in the serine synthesis pathway is coupled to a conversion of l-glutamate to 2-ketoglutarate.