The right answer is noble gases.
The noble gases, or rare gases, are the chemical elements of group 18 (formerly "group VIIIA" or even "group 0") of the periodic table. These are helium He, neon 10Ne, argon 18Ar, krypton 36Kr, xenon 54Xe and radon 86Rn, the latter being radioactive.
This property means that they can not bind with other atoms to form molecules or lose electrons to transform into ions, hence their name noble or inert gases (they are not very active and do not do not mix). In nature, all elements "want" to become stable.
Answer:
Positive
Explanation:
For the most effective hot pack, the temperature change should be <u>positive</u>.
<em>Hot packs are generally utilized for their heat-producing abilities. Hence, the reactions leading to the activation of hot packs are usually exothermic, that is, heat energy generating. In other words, positive or increased temperatures must be generated when hot packs are activated.</em>
This is unlike cold packs which are utilized for the cold-generating abilities. Reactions leading to their activations must be endothermic, that is, heat-absorbing.
Answer:
Butanoic Acid:
I have attached the structure of Butanoic Acid. Please refer to the attachment.
Explanation:
Solution:
First of all, we need to calculate the double bond equivalent (DBE) for the compound given:
Compound = C4H8O2
DBE = (C +1) - (H + X - N)/2
C = no. of carbons
H = no. of Hydrogen
X = no. of Halogens
N = no. of Nitrogen
DBE = (4+1) - (8/2)
DBE = 5-4
DBE = 1
It indicates the presence of 1 double bond in the possible structure.
Further structure can be identified by looking the peak values of the spectrum. So, we have,
2500 - 3300 = it indicates the presence of -COOH group
1720 = it indicates the (C=0) stretching
1200 = It indicates the (C-O) stretching
SO, the possible structure is
Butanoic Acid:
I have attached the structure of Butanoic Acid. Please refer to the attachment.
For the discovery of the elements polonium and radium. Prohibited from higher education in her native Poland (then controlled by Russia), she moved to Paris in 1891 and studied at the Sorbonne.
Polyatomic ion: a covalently bonded group of atoms that has a positive or negative charge and acts as a unit.
