Which of the following describes the change in atomic mass and atomic number during this reaction?
The mass number tells us the number (the sum of nucleons) of protons and neutrons in the nucleus of an atom. ... It is traditionally represented by the symbol Z. The atomic number uniquely identifies a chemical element. In an atom of neutral charge, atomic number is equal to the number of electrons.
An 18-karat gold necklace is 75% gold by mass, 16% silver, and 9.0% copper.A. What is the mass, in grams, of the necklace if it contains 0.24 Oz of silver? B. How many grams of copper are in the necklace.? C. If the 18- karat gold has a density of 15.5g/cm^3, what is the volume in cubic centimeters?
B. How many grams of copper are in the necklace.?
I think that the answer would be option B.
Polychlorinated biphenyls (PCBs) are major environmental pollutants. Which of the following detectors would be most sensitive for GC analysis of PCBs? (24-8) Group of answer choices flame photometric (FPD) electron capture (ECD) flame ionization (FID) thermal conductivity (TCD) nitrogen-phosphorus (NPD)
electron capture detectors (ECD)
Electron capture detectors (ECD) would be most sensitive for GC analysis of PCBs.
Answer: The detectors that would be most sensitive for GC analysis of PCBs are
- Electron Capture Detectors (ECD)
Polychlorinated biphenyls(PCBs) are oily chemicals that are manufactured(man-made) and used as lubricants in electrical equipments such as transformers. They are grouped as major environmental pollutants because they are characterised as being very stable, as they are resistant to extreme temperature and pressure. Therefore with time the build up in the environment and can cause harmful health effects.
In the environment, it can be found distributed virtually everywhere incl, air water or soil. The PCBs can be analysed in the environment through the use of gas chromatography( GC) with electron capture detector (ECD) as the most sensitive detector. The method was found to be more sensitive as the number of chlorine atoms attached to the biphenyl increases.
Why does sodium chloride form a crystal lattice
Ions of opposite charge strongly attract each other; those of like charges repel. As a result ions in an ionic compound are arranged in a particular manner.
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Draw all the structural isomers for the molecular formula C3H8O. Be careful not to draw any structures by crossing one line over another; the system needs to know where you intend connections to be between atoms.
The three isomers having the molecular formula are drawn in the figure below.
The reform reaction between steam and gaseous methane () produces "synthesis gas," a mixture of carbon monoxide gas and dihydrogen gas. Synthesis gas is one of the most widely used industrial chemicals, and is the major industrial source of hydrogen. Suppose a chemical engineer studying a new catalyst for the reform reaction finds that liters per second of methane are consumed when the reaction is run at and . Calculate the rate at which dihydrogen is being produced. Give your answer in kilograms per second. Round your answer to significant digits..
The reform reaction between steam and gaseous methane (CH4) produces "synthesis gas," a mixture of carbon monoxide gas and dihydrogen gas. Synthesis gas is one of the most widely used industrial chemicals, and is the major industrial source of hydrogen.
Suppose a chemical engineer studying a new catalyst for the reform reaction finds that 924 liters per second of methane are consumed when the reaction is run at 261°C and 0.96atm. Calculate the rate at which dihydrogen is being produced. Give your answer in kilograms per second. Round your answer to 2 significant digits.
Answer: The rate at which dihydrogen is being produced is 0.12 kg/sec
The balanced chemical equation is ;
According to ideal gas equation:
P = pressure of gas = 0.96 atm
V = Volume of gas = 924 L
n = number of moles
R = gas constant =
T =temperature =
According to stoichiometry:
1 mole of methane produces = 3 moles of hydrogen
Thus 20.2 moles of methane produces = moles of hydrogen
Mass of hydrogen =
Thus the rate at which dihydrogen is being produced is 0.12 kg/sec
For the experiments from 1-3 with the same temperature change, what other parameters are the same at the initial reaction conditions?a. mmol HCl total mL solution b. mmol NaOH Initial concentration of NaOH c. mL H2O Initial concentration of HCl
The following parameters:
total mL solution
initial concentration of NaOH
The options have been incorrectly arranged in the question statement given here. The three conditions mentioned above are what would be observed to remain the same when this experiment is carried out.