The whitening toothpastes showed differences in their physical-chemical properties. All toothpastes promoted changes to the surface, probably by the use of a bleaching agent.
Explanation:
Contributing structures are the resonating structures which are formed due to the delocalization of electrons in a molecule.
The azide ion that is
, is a symmetrical ion, all of whose contributing structures have formal charges.
Lone pair of central nitrogen atom in azide ion is in conjugation with the neighboring nitrogen atoms.
Contributing structures of azide ion are drawn in the image attached.
Answer:
Please refer to the attachment for answers.
Explanation:
Please refer to the attachment for explanation
Answer:
A. Neither the subjects nor the researchers can bias the results.
Explanation:
As described, a double- blind study is one in which the researcher and his study does not know the person receiving the actual treatment.
Researchers can be bias in their studies as they seek to establish and fine tune results in the way the best favors them. A double-blind study helps to bridge this gap to prevent bias that might be introduced into an experimental set up or while interpreting results.
(a) 33.6 L of oxygen would be produced.
(b) 106 grams of
would be needed
<h3>Stoichiometric calculations</h3>
1 mole of gas = 22.4 L
(a) From the equation, 2 moles of
produce 3 moles of
. 1 mole of
will, therefore, produce 1.5 moles of
.
1.5 moles of oxygen = 22.4 x 1.5 = 33.6 L
(b) 22.4 L of
is produced at STP. This means that 1 mole of the gas is produced.
From the equation, 1 mole of
requires 1 mole of
.
Molar mass of
= (23x2)+ (12)+(16x3) = 106 g/mol
Mass of 1 mole
= 1 x 106 = 106 grams
More on stoichiometric calculations can be found here: brainly.com/question/27287858
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