First we must understand the balanced chemical equation:
Pb(NO3)2 + K2CrO4 ==> PbCr04 + 2KNO3
This shows us that two moles of potassium nitrate are formed from 1 mole of lead nitrate or potassium chromate solution. The next step is to find out how many moles of each reactant there are. Note the word Molar is a concentration that simply means moles per liter.
2.25L of 1.5M lead nitrate = 2.25x1.5 = 3.375 moles of lead nitrate
1.15L of 2.75M potassium chromate = 1.15x2.75 = 3.1625 moles
The important part here is to see that the number of moles of the reactants are different. We know the number of moles of products will be dependent on the number of moles of reactants, and in this case there is less potassium chromate than there is lead nitrate, so this is the limiting factor as there is a one to one relationship with both reactants. Therefore, the number of moles of potassium nitrate produced is 2 x number of moles of potassium chromate. i.e. 6.325 moles of potassium nitrate is liberated.
To work out the number of grams, we must find the molar mass (the mass of one mole) of KNO3, which is the sum of the molar mass of each of its component atoms that make up the molecule. I've looked this up as 101.1 grams per mole.
Now we simply times the molar mass by the number of moles to yield the final grams liberated: 6.325 moles x 101.1 grams/mole = 639.4 grams of potassium nitrate is liberated from this reaction.
Answer:
Research
Explanation:
Research is a deliberate attempt to find answer or solution to a problem along with help of observation, study, survey, comparison, literature review and experimentation.
It is in other way a search for knowledge through systematic way of finding solutions to a problem.
The research methodology comprises of following stages –
Stage I – Observing a problem
Stage II – Formulating a hypothesis
Stage III – Collecting the data
Stage IV – Analysis of facts and data
Stage V – Finding a solution or reaching a conclusion
Answer:
Background
During the course of a bacterial infection, the rapid identification of the causative agent(s) is necessary for the determination of effective treatment options. We have developed a method based on a modified broad-range PCR and an oligonucleotide microarray for the simultaneous detection and identification of 12 bacterial pathogens at the species level. The broad-range PCR primer mixture was designed using conserved regions of the bacterial topoisomerase genes gyrB and parE. The primer design allowed the use of a novel DNA amplification method, which produced labeled, single-stranded DNA suitable for microarray hybridization. The probes on the microarray were designed from the alignments of species- or genus-specific variable regions of the gyrB and parE genes flanked by the primers. We included mecA-specific primers and probes in the same assay to indicate the presence of methicillin resistance in the bacterial species. The feasibility of this assay in routine diagnostic testing was evaluated using 146 blood culture positive and 40 blood culture negative samples.
Explanation:
Results
Comparison of our results with those of a conventional culture-based method revealed a sensitivity of 96% (initial sensitivity of 82%) and specificity of 98%. Furthermore, only one cross-reaction was observed upon investigating 102 culture isolates from 70 untargeted bacteria. The total assay time was only three hours, including the time required for the DNA extraction, PCR and microarray steps in sequence.
Answer:
Monosaccharides
Explanation:
A monosaccharide is a monomer of a carbohydrate. Macromolecules are made up of monomers!
