Answer:
A. percentage mass of iron = 5.17%
percentage mass of sand = 8.62%
percentage mass of water = 86.205%
B. (Iron + sand + water) -------> ( iron + sand) ------> sand
C. The step of separation of iron and sand
Explanation:
A. Percentage mass of the mixtures:
Total mass of mixture = (15.0 + 25.0 + 250.0) g =290.0 g
percentage mass of iron = 15/290 * 100% = 5.17%
percentage mass of sand = 25/290 * 100% = 8.62%
percentage mass of water = 250/290 * 100% = 86.205%
B. Flow chart of separation procedure
(Iron + sand + water) -------> separation by filtration using filter paper and funnel to remove water --------> ( iron + sand) -----------> separation using magnet to remove iron ------> sand
C. The step of separation of iron and sand by magnetization of iron will have the highest amount of error because during the process, some iron particles may not readily be attracted to the magnet as they may have become interlaced in-between sand grains. Also, some sand particle may also be attracted to the magnet as they are are borne on iron particles.
1.Hans and Zacharias Janssen created the first microscope.
2.Robert Hooke was the first to use the word “cell.”
3.Anton van Leeuwenhoek observed small organisms he called “animalcules.”
4.Matthias Schleiden theorized that plants are made of cells.
5.Theodor Schwann theorized that animals are made of cells.
6.Rudolf Virchow theorized that cells come from other pre-existing cells.
Answer: A persistent or non-volatile chemical agent can remain on a surface for more than 24 hours.
Explanation:
Non-volatile substance is defined as the one which does not readily evaporate into its surrounding. Generally, a non-volatile substance has strong intermolecular forces between its molecules.
A non-volatile substance will take more than 24 hours to remain on the surface.
On the other hand, a substance with weak intermolecular forces present in its molecules will readily evaporate into the atmosphere.
For example, acetic acid is a volatile substance and quickly evaporates into the atmosphere.
Thus, we can conclude that a persistent or non-volatile chemical agent can remain on a surface for more than 24 hours.
The mass of air in the scuba tank is 841.614 g.
Using the ideal gas equation;
PV=nRT
P = pressure of the gas = 195 kPa
V = volume of the gas = 350 L
n = Number of moles of the gas = ??
R = molar gas constant = R = 8.314 J K-1 mol-1
T = temperature of the gas = 10 °C or 283 K
n = PV/RT
n = 195 * 350/8.314 * 283
n = 68250/2352.862
n = 29.00 moles
Number of moles = mass/molar mass
mass of air = Number of moles * molar mass
mass of air = 29.00 moles * 29g/mol
Mass of air = 841.614 g
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<span>Both plants and animals fight pathogens is because both have an ant. </span><span>The answer is B.
P</span>athogens is <span>a bacterium, virus, or other microorganism that can cause disease.
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