Answer: Ethyl Ethanoate can be used as a developing solvent. It’s safer.
Explanation:Di ethyl ether should be carefully used because it’s highly flammable and intoxicating when inhaled and can cause explosions because of its high reactivity to air and light.
The initial mass of sodium hydroxide is 3.3 g (answer C)
<u><em>calculation</em></u>
Step 1 : find the moles of iron (ii) hydroxide ( Fe(OH)₂
moles = mass÷ molar mass
from periodic table the molar mass of Fe(OH)₂ = 56 + [16 +1]2 = 90 g/mol
moles is therefore = 3.70 g÷ 90 g/mol = 0.041 moles
Step 2: use the mole ratio to calculate the moles of sodium hydroxide (NaOH)
from given equation NaOH : Fe(OH)₂ is 2 :1
therefore the moles of NaOH = 0.041 x 2 = 0.082 moles
Step 3: find mass of NaOH
mass = moles x molar mass
from the periodic table the molar mass of NaOH = 23 +16 +1 = 40 g/mol
mass = 0.082 moles x 40 g/mol = 3.3 g ( answer C)
This question is incomplete because the options are missing; here are the options:
Which of the following is LESS dense than water?
The spoon
The glass
The tablets
The bubbles
The correct answer to this question is The bubbles
Explanation:
In general, the density of materials and substances affects their buoyancy. This implies in water less dense materials will float and those with higher density will sink. In the situation presented, the only element that is less dense than water are bubbles; this is shown by the movement of the bubbles as these originate in the bottom of the glass of water but they rise to the surface, which shows they are less dense than water.
Answer:
The correct answer is because they have same number of protons but different number of neutrons.
Explanation:
Isotopes are atoms of the same element but differ only in the number of neutrons in the nucleus, i.e. they have same atomic number but different mass number.
Mass number is affected as they have different number of neutrons, thus effecting their physical properties.
The number of electrons and protons are same, i.e. their atomic number is same and thus their chemical properties are same as chemical properties are determined by the atom’s electronic configuration and that relates to number of protons.
Answer:
Option (D) is definitely the answer.
Explanation:
Before going further, it is important to know what buffers and pH represent, which are keywords to answering this question.
Buffers is a special solution that can withstand or resist changes due to pH levels which may be as a result of an introduction of acidic or basic components into the blood. In other words, they maintain the stability of pH level in the human blood.
pH blood levels on the other hand, can be grouped into three: acidity, neutrality and alkalinity. Using a pH scale, one can determine its current level. In the human blood the pH level is near neutral and needs to be on a level near 7.4 in order to avoid a high rise or a drastic fall even if acidic or basic components come in or departs the blood stream.
Therefore, if one of the buffers that contributes to pH stability in human blood is carbonic acid, which is as a result of a combination of carbon dioxide and water in the blood stream. On getting to the lungs it is converted to water and subsequently released as waste. Maintaining this stability will definitely be to decrease the concentration of carbonic acid and increase that of water instead.
