Answer:
20.9%
Explanation:
- The percentage by mass of solution is given by dividing the mass of solute in grams by the mass of solution in grams then multiplying it by 100%.
% Mass of solution = mass of solute/mass of solution × 100%
= (27.0 g/ 129.0 g) × 100%
= 20.93%
= 20.9%
Answer:- molar mass of the unknown gas is 71.5 gram per mol.
Solution:- From Graham's law of effusion rates, the rate of effusion of a gas is inversely proportional to the square root of it's molar mass.
When we compare the effusion rates of two gases then the formula for Graham's law is:

In this formula, V stands for volume and M stands for molar mass
Rate is volume effused per unit time. Since, the volumes are same, the formula could be written as:

let's say in formula, subscript 1 is for hydrogen gas and 2 is for the unknown gas.
Molar mass of hydrogen is 2.02 grams per mol and the time taken to effuse it is 2.42 min. The time taken to effuse the unknown gas is 14.4 min and we are asked to calculate it's molar mass. let's plug in the values in the formula:


doing squares to both sides:



So, the molar mass of the unknown gas is 71.5 grams per mol.
Answer:
Endoplasmic reticulum.
Explanation:
Second messengers are known as intracellular signaling molecules released from the cell in response to exposure to extracellular signaling molecules. Second messenger activate physiological changes at a cellular level, for example proliferation, migration, differentiation, survival, and apoptosis.
Calcium ions are hydrophilic, water-soluble molecules. They are present in intracellular component know as endoplasmic reticulum and quickly released when needed. They are necessary for many important functions including fertilization, muscle contractions, and neurotransmitter release.
Answer:
I'd say ALL OF THE ABOVE.
A Mechanical wave is a disturbance that transfers energy as it moves through a medium without displacement of the medium itself.
It can Either be Transversal or Longitudinal.
It is Transversal when the particles of the medium move perpendicular to the wave motion.
It requires a medium and begin at a source with a disturbance
So
ALL THE OPTIONS SEEM LEGIT.
Answer: Science is a particular way of knowing about the world. In science, explanations are restricted to those that can be inferred from confirmable data—the results obtained through observations and experiments that can be substantiated by other scientists. Anything that can be observed or measured is amenable to scientific investigation. Explanations that cannot be based on empirical evidence are not a part of science.
Explanation: