You have to be very careful with this question. A change in mass can also occur in chemical changes especially if you have too much of something. For example
CH4 + 1.5 02 ===> CO2 + H2O
If you have too much of either CH4 or O2, there will be some CH4 or O2 left over. There has been a change in mass that you have too much of.
However that is not the point of the question. It is just something you need to be aware of.
Suppose you have a piece of aluminum and you take a course grinder after it. You will change the texture of the side you took the grinder to. If the aluminum has been anodized (a color has been put on it's surface), you may grind the color off or if it is just plain aluminum, you may roughen the surface, but you won't change what the aluminum will do chemically.
You may need only a small portion of the aluminum and you grind off just what you need. That will change the mass of both what you took off and the piece that you want, but the aluminum will still do whatever chemical property you need to use.
So you can change both texture and mass without changing the chemical properties of the substance whose mass or texture you are changing.
Genetic: an organism uses energy for cellular respiration, and has all the genes necessary to make the proteins to accomplish it.
Answer:
The correct answer is "D. The difference in their electronegativities is greater than 1.7"
Explanation:
An ionic bond is produced between metallic and non-metallic atoms, where electrons are completely transferred from one atom to another. During this process, one atom loses electrons and another one gains them, forming ions. Usually, the metal gives up its electrons forming a cation to the nonmetal element, which forms an anion.
So, this type of bond consists of the attraction of atoms with electric charges of different signs, that is, the bond is established when atoms of low electronegative elements (metals) are bonded with atoms of highly electronegative elements (nonmetals).
So you can say that atoms of electronegativity difference equal to or greater than 1.7 participate in this type of bond (with its exceptions).
<u><em>The correct answer is "D. The difference in their electronegativities is greater than 1.7"</em></u>
I believe the answer is the first one <span>NaH</span>
Answer:
Limitations of litmus paper and phenolphthalein:
They do not give the numerical pH value.
Can differentiate only between a very strong acid and base.
The colour change can be for reasons other than acid- base reactions.
Explanation:
The litmus test is quick and simple, but it suffers from a few limitations. First, it's not an accurate indicator of pH; it does not yield a numerical pH value. Instead, it roughly indicates whether a sample is an acid or a base. Second, the paper can change colors for other reasons besides an acid-base reaction.
