Answer:
H2(g)+I2(s)→2HI(s)
Explanation:
Hello there!
In this case, according to the given information and unbalanced chemical reaction, we infer it must be balanced in agreement with the law of conservation of mass because the reactants side has two hydrogen and iodine atoms whereas the products side has just one. In such a way, by placing a 2 on HI, we obtain the following balanced reaction:
H2(g)+I2(s)→2HI(s)
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Yes it can cause chemical change
Answer:
Four covalent bonds.
Explanation:
Hello,
In this case, given the attached picture in which you can find the Lewis dot structure for metanal (formaldehyde) we can see two C-H bonds and two C-O bonds via a double bond, thus, we can compute the type of each bond given the electronegativities of hydrogen, carbon and oxygen which are 2.1, 2.5 and 3.5 respectively:

Thus, since both electronegativity difference are less 1.7 we infer that all of them are covalent, therefore, it has four covalent bonds, two C-H bonds and a double C-O bond.
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I think I it’s gonna be C.
Answer:
The water soluble substance which absorb moisture from the air and then dissolve on the absorbed moisture to change into liquid taste are called deliquescent substances whereas the substances which absorb moisture from air but do not change their state are called hygroscopic substances.