Answer:
Q = -33.6kcal .
Explanation:
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In this case, according to the equation for the calculation of the total heat of reaction when a fixed mass of a fuel like ethane is burnt, we can write:
Whereas n stands for the moles and the other term for the enthalpy of combustion. Thus, for the required total heat of reaction, we first compute the moles of ethane in 3 g as shown below:
Next, we understand that -337.0kcal is the heat released by the combustion of 1 mole of ethane, therefore, to compute Q, we proceed as follows:
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From the calculations, the half life of the material is 6.5 days.
<h3>What is radioactivity?</h3>
The term radioactivity has to do with the spontaneous disintegration of a specie.
Uisng the formula;
N=Noe^-kt
N= amount at time t = 0.135 Ci or 4.995 ×10^9 Bq
No = amount initially present = 1.75 x 10^12 Bq
k = rate constant = ?
t = time taken = 55 days
Hence;
4.995 ×10^9 = 1.75 x 10^12e^-55k
4.995 ×10^9/1.75 x 10^12 = e^-55k
2.85 * 10^-3 = e^-55k
ln2.85 * 10^-3 = -55k
k = ln2.85 * 10^-3/-55
k = 0.1066 day-1
Half life = 0.693/ 0.1066 day-1
= 6.5 days
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Answer:
Oxygen = 15.999 g/mol
Iron = 3 × 55.845 = 167.535 g/mol
CaCO3 = 20 × 100.0869 = 2001.738 g/mol
Answer:
b.) Br and Br
Explanation:
A covalent bond occurs when electrons are shared between two atoms causing them to form a bond.
A "pure" covalent bond refers to a nonpolar covalent bond. In these bonds, the electrons are shared equally between two atoms as a result of the absence of an (or very small) electronegativity difference. The purest covalent bond would therefore be between two atoms of the same electronegativity. Two bromines (Br) have the same electronegativity, thus making it the purest covalent bond.
Polar covalent bonds occur when electrons are shared unequally between two atoms. There is a larger electronegativity difference between the two atoms, but not large enough to classify the bonds as ionic. In this case, a.) and c.) are polar covalent bonds and d.) is an ionic bond.
In prolonged fasting conditions acetyl-coa generated from the breakdown of amino acids and fatty acids does not enter the citric acid cycle in the liver, but acetyl-coa derived from ketone bodies can enter the citric acid cycle in the brain. <u>Cholesterol is required in the diet.</u>
<h3>What is
amino acids?</h3>
Amino acids are chemical molecules having side chains (R groups) unique to each amino acid as well as amino and carboxylic acid (CO2H) functional groups.
Every amino acid contains the elements carbon (C), hydrogen (H), oxygen (O), and nitrogen (N) (CHON); in addition, the side chains of cysteine and methionine contain sulfur (S), while the less frequent amino acid selenocysteine has selenium (Se). As of 2020, it is known that more than 500 naturally occurring amino acids make up the monomer units of peptides, including proteins.
Despite the fact that there are only 22 proteins, 20 of them have unique specified codons, and another two have unique coding mechanisms: All eukaryotes contain selenocysteine, and pyrrolysine is also present.
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