the answer is dure light I'm not sure of this answer ,but it might be to go with .
The right answer is screening test.
In medicine, screening consists of looking for one or more diseases or abnormalities known as "at risk" in individuals of a given population.
These investigations are followed or not by medical consultations, clinical examinations and treatments.
In addition, screening is a preliminary procedure (test or examination) to detect one or more characteristic signs or symptoms of a disease or syndrome and potentially leading to further investigation.
<span>9.40x10^19 molecules.
The balanced equation for ammonia is:
N2 + 3H2 ==> 2NH3
So for every 3 moles of hydrogen gas, 2 moles of ammonia is produced. So let's calculate the molar mass of hydrogen and ammonia, starting with the respective atomic weights:
Atomic weight nitrogen = 14.0067
Atomic weight hydrogen = 1.00794
Molar mass H2 = 2 * 1.00794 = 2.01588 g/mol
Molar mass NH3 = 14.0067 + 3 * 1.00794 = 17.03052 g/mol
Moles H2 = 4.72 x 10^-4 g / 2.01588 g/mol = 2.34140921086573x10^-4 mol
Moles NH3 = 2.34140921086573x10^-4 mol * (2/3) = 1.56094x10^-4 mol
Now to convert from moles to molecules, just multiply by Avogadro's number:
1.56094x10^-4 * 6.0221409x10^23 = 9.400197448261x10^19
Rounding to 3 significant figures gives 9.40x10^19 molecules.</span>
<span>The rate of effusion of a gas is inversely proportional to the square root of the molecular weight of the species. Now there will be differences among isotopomers but neglecting these and taking the avg mol wt of N2 = 28 and Xe = 132;
Rate(N2)/Rate(Xe) = sqrt (132/28) = 2.17</span>
Answer:
Explanation:
Hello!
In this case, since the freezing point depression caused by the addition of a solute, we use the following formula:
Thus, we first need to compute the molality of each solute, as shown below:
Next, since NaCl has two ionic species, one Na⁺ and one Cl⁻, and CaCl₂ three, one Ca²⁺ and two Cl⁻, the van't Hoff's factors are 2 and 3 respectively, therefore the freezing point depressions turn out:
It means that CaCl₂ is still better than NaCl because produces involves a higher melting point for the ice, so it would melt faster.
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