The much of the sample that would remain unchanged after 140 seconds is 2.813 g
Explanation
Half life is time taken for the quantity to reduce to half its original value.
if the half life for Scandium is 35 sec, then the number of half life in 140 seconds
=140 sec/ 35 s = 4 half life
Therefore 45 g after first half life = 45 x1/2 =22.5 g
22.5 g after second half life = 22.5 x 1/2 =11.25 g
11.25 g after third half life = 11.25 x 1/2 = 5.625 g
5.625 after fourth half life = 5.625 x 1/2 = 2.813
therefore 2.813 g of Scandium 47 remains unchanged.
Answer:
The mass of this 25 mL supercritical CO2 sample has a mass of 11.7g
Explanation:
Step 1: Given data
The supercritical CO2 has a density of 0.469 g/cm³ (or 0.469 g/mL)
The sample hasa volume of 25.0 mL
Step 2: Calculating mass of the sample
The density is the mass per amount of volume
0.469g/cm³ = 0.469g/ml
The mass for a sample of 25.0 mL = 0.469g/mL * 25.0 mL = 11.725g ≈ 11.7g
The mass of this 25 mL supercritical CO2 sample has a mass of 11.7g
Gay-Lussac's law gives the relationship between pressure and temperature of gas. For a fixed amount of gas, pressure is directly proportional to temperature at constant volume.
P/T = k
where P - pressure , T - temperature and k - constant
parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation
substituting the values in the equation
T = 4342 K
initial temperature was 4342 K
Answer:
True
Explanation:
Stars are bright and enormous astronomical bodies that are located at a large distance from the earth. They are made up of the lightest gaseous elements namely hydrogen and helium. These hydrogen atoms undergo the reaction of nuclear fusion, which fuels the energy of the star and allows the star to shine, releasing a large amount of energy. They are located about trillions of miles away from the location of the earth, due to which they appear smaller in size.
Thus, the above-given statement is True.
Chemical weathering is caused by rain water reacting with the mineral grains in rocks to form new minerals (clays) and soluble salts. These reactions occur particularly when the water is slightly acidic.
