Magnetic energy from the magnet applies a force to the compass needle causing it to move
Answer:
D. -120.9 kJ
Explanation:
According to Hess's law ,the total enthalpy change for a reaction is the sum of all changes regardless of the stages or the steps of the reaction.
....(1)

(this reaction should be reversed in order to reach the required reaction )
On reversing the reaction the sign of
get reversed.
(In this case change sign from '-' to'+'. Hence
= + 65 kJ)
....(1)
......(2)
Adding equation (1) and (2)
![Ca(OH)_{2} + 2HCl \rightarrow CaCl_{2} + 2H_{2}O[tex][tex]Delta H = - 186 + 65 = - 121\kJ](https://tex.z-dn.net/?f=%3Cstrong%3ECa%28OH%29_%7B2%7D%20%2B%202HCl%20%5Crightarrow%20CaCl_%7B2%7D%20%2B%202H_%7B2%7DO%3C%2Fstrong%3E%5Btex%5D%3C%2Fp%3E%3Cp%3E%5Btex%5D%3Cstrong%3EDelta%20H%20%3D%20-%20186%20%2B%2065%20%3D%20-%20121%5CkJ%3C%2Fstrong%3E)
(It is nearly equal to -120.9 kJ)
Answer:
75 kJ/mol
Explanation:
The reactions occur at a rate, which means that the concentration of the reagents decays at a time. The rate law is a function of the concentrations and of the rate constant (k) which depends on the temperature of the reaction.
The activation energy (Ea) is the minimum energy that the reagents must have so the reaction will happen. The rate constant is related to the activation energy by the Arrhenius equation:
ln(k) = ln(A) -Ea/RT
Where A is a constant of the reaction, which doesn't depend on the temperature, R is the gas constant (8.314 J/mol.K), and T is the temperature. So, for two different temperatures, if we make the difference between the two equations:
ln(k1) - ln(k2) = ln(A) - Ea/RT1 - ln(A) + Ea/RT2
ln (k1/k2) = (Ea/R)*(1/T2 - 1/T1)
k1 = 8.3x10⁸, T1 = 142.0°C = 415 K
k2 = 6.9x10⁶, T2 = 67.0°C = 340 K
ln(8.3x10⁸/6.9x10⁶) = (Ea/8.314)*(1/340 - 1/415)
4.8 = 6.39x10⁻⁵Ea
Ea = 75078 J/mol
Ea = 75 kJ/mol
Answer:
6.6666666667 feet per second I believe
Answer :
Amino acids join by forming (1) peptide bonds. Water is released.
The chains of amino acids vary according to their (2) side chains, which each have differing makeup.
These chains determine the protein’s structure and they fold to create a unique (3) third-dimensional shape.
Explanation :
Amino acid : The amino acids are the building blocks of protein. Amino acids are the compound which consist both amine
and carboxylic
groups along with the side chains. In the protein, many amino acids are linked by the peptide bonds.
Th peptide bonds are formed by the combining of amino group of one amino acid to the carboxylic group of another amino acid by releasing of water.
Some examples of amino acids are glycine, lysine, alanine, etc.
Peptide bond formation image is shown below.
In the image 'R' can be contained by different groups like hydrogen, methyl, phenyl, etc