﻿ Which expression represents the ∆H for a chemical reaction in terms of the potential energy, PE, of its products and reactants? A) PE of products + PE of reactants B) PE of products – PE of reactants C) PE of reactants × PE of products D) PE of products ÷ PE of reactants E) PE of reactants – PE of products - AssignmentGrade.com

# Which expression represents the ∆H for a chemical reaction in terms of the potential energy, PE, of its products and reactants? A) PE of products + PE of reactants B) PE of products – PE of reactants C) PE of reactants × PE of products D) PE of products ÷ PE of reactants E) PE of reactants – PE of products

QUESTION POSTED AT 01/06/2020 - 02:51 PM

The answer is the option B) PE of products - PE of reactants.

This is, the change of energy, in the form of heat, ΔH, for a chemical reaction is the potential energy of products less the potential energy of reactants: ΔH = PE products - PE reactants.

1) when the potential energy increases, PE of products - PE of reactants > 0 => ΔH > 0, =>the reaction is absorbing energy and it is endothermic;

2) when potential energy decreases PE of products - PE of reactants < 0 => ΔH < 0, the reaction is releasing energy and it is exothermic.

Those are terms very used in chemistry and thermodynamics.

## Related questions

### Shows quantities and how they vary by other factors A. bar graph B. line graph. C. circle graph

QUESTION POSTED AT 02/06/2020 - 02:03 AM

### Describe how oxidation and reduction involve electrons, change oxidation numbers, and combine in oxidation-reduction reactions.

QUESTION POSTED AT 02/06/2020 - 01:42 AM

### Calculate the mass of excess reagent remaining at the end of the reaction in which 90.0 g of SO2 are mixed with 100.0 g of O2

QUESTION POSTED AT 02/06/2020 - 01:40 AM

### Which pairing below does not correctly match the scientist with the contribution to the understanding of the atom? A. Proust and the realization that the elements of compounds are found in certain proportions by mass B. Rutherford and the understanding that the atom has a small, dense nucleus with a positive charge C. Thomson and the law of definite proportions D. Dalton and the initial proposal of the atomic theory of matter

QUESTION POSTED AT 02/06/2020 - 01:36 AM

### What volume of 0.3682 M H2SO4 solution is required to react with 0.4198 grams of Al(CN)3 according to the reaction, 2 Al(CN)3 + 3 H2SO4  6 HCN + Al2(SO4)3?

QUESTION POSTED AT 02/06/2020 - 01:34 AM

### Which of the following correctly describes how rate laws are determined? Rate laws can be determined from the coefficients of balanced equations. The rate law for an elementary step can only be determined from unimolecular reactions. The rate law for the overall reaction is always determined by the rate law of the fastest step. Rate laws are determined through experimentation.

QUESTION POSTED AT 02/06/2020 - 01:33 AM

### Which of the following is a sign of a chemical reaction?

QUESTION POSTED AT 02/06/2020 - 01:33 AM

### What kinds of bonds make up a formula unit of sodium chloride? a. Ionic bonds c. 1 ionic bond and 1 covalent bond b. Covalent bonds d. Van der Waals forces

QUESTION POSTED AT 02/06/2020 - 01:29 AM

### Nuclear fission: A produces less waste than fusion B creates more air pollution than burning fossil fuels C often causes thermal pollution of water sources D all of the above

QUESTION POSTED AT 01/06/2020 - 04:45 PM

### Burning a piece of wood in fire can be best described as a chemical change because the atoms in wood change their state. physical change because the atoms in wood are turned into a gaseous product. chemical change because the atoms in wood and oxygen are rearranged. physical change because the atoms in wood are turned into black ash.

QUESTION POSTED AT 01/06/2020 - 04:40 PM

### If two atoms are bonded with a bond energy of 87 kJ, what must be done to break the bond? A. 87 kJ of energy must be added B. The energy must be decreased by 87 kJ. C. The bond order has to be higher. D. No energy should come out or go in.

QUESTION POSTED AT 01/06/2020 - 04:38 PM

### J.C. wants to determine if there is a relationship between room color and sleep. Based on his research, J.C. makes an educated guess that people fall asleep more quickly in a room painted blue than in a room painted yellow. He asks several people which color they like better, yellow or blue, and uses their responses to see if his educated guess was correct. What is missing from J.C.'s scientific investigation? a. experiement testing hypothesis b. research on topic to see what others learned. c.hypothesis based on research that can be tested d.analysis of responses from all test subjects

QUESTION POSTED AT 01/06/2020 - 04:37 PM

### According to Coulomb’s law, which ionic compound A–D has the smallest electrostatic potential energy (i.e., closest to zero)? The size of the anion increases in the order F < Cl < Br < I.

QUESTION POSTED AT 01/06/2020 - 04:24 PM

### What is the units of k in the following expression: rate = k[A][B]? A) s^-1 B)M^-1 s^-1 C)M^-2 s^-1 D)M

QUESTION POSTED AT 01/06/2020 - 04:19 PM

### What is the net ionic equation for the following reaction? H2CrO4 + Ba(OH)2

QUESTION POSTED AT 01/06/2020 - 04:16 PM

### For an exothermic reaction, what effect will increasing the temperature have on equilibrium?

QUESTION POSTED AT 01/06/2020 - 04:14 PM

### Why do electrons enter the 4s orbital before entering the 3d orbital? because the 3d orbital is at a lower energy level because both the 4s and 3d orbitals are at the same energy level because the 4s orbital is at a lower energy level because the 4s orbital is at a higher energy level

QUESTION POSTED AT 01/06/2020 - 04:13 PM

### Which of the following are potential benefits of wind turbines? (may be more than one answer) A. viable source of power B. creates less pollution C. is expensive to set up D. is a renewable energy source

QUESTION POSTED AT 01/06/2020 - 04:07 PM

### What causes water molecules to have the shape they have, according to VSEPR theory? A. ionic attraction and repulsion B. the unusual location of the free electrons C. repulsive forces between specific electrons D. interaction between the fixed orbitals of the unshared pairs of oxygen

QUESTION POSTED AT 01/06/2020 - 04:07 PM

### The molar masses of three gases, A, B, and C, are 4 grams, 16 grams, and 32 grams respectively. Which sentence represents the effusion rates of these gases? A). A < B < C B). C < B < A C). B < C < A D). B < A < C

QUESTION POSTED AT 01/06/2020 - 04:05 PM

### Which arrows represents the phase transitions in which he's energy is gained

QUESTION POSTED AT 01/06/2020 - 04:03 PM

### Sodium salicylate is made from carbons dioxide and sodium phenoxide. Identify each of these substances as a reactant or a product

QUESTION POSTED AT 01/06/2020 - 03:57 PM

### If a star is considered medium-sized, it is a) about the size of our sun b) about half the size of our sun c) about twice the size of our sun d) at least five times the size of our sun

QUESTION POSTED AT 01/06/2020 - 03:53 PM

### The elements located in the first column, or group, in the periodic table all share a similar electron configuration. If the atom is neutral, how many electrons are found in the outermost shell of each of these elements? A=1 B=2 C=3 D=4

QUESTION POSTED AT 01/06/2020 - 03:52 PM

### Describe geothermal energy and give one advantage and one disadvantage of its use.

QUESTION POSTED AT 01/06/2020 - 03:51 PM

### ]If a sample of pure iodine contains 4.69 x 1022 atoms of iodine, how many moles of iodine are in the sample? A=0.08 B=0.13 C=7.78 D=12.84

QUESTION POSTED AT 01/06/2020 - 03:50 PM

### What is electronegativity? A. a measurement of the ability of an atom to attract a proton B. a measurement of the ability of an atom to attract a neutron C. a measurement of the ability of an atom to attract an electron D. a measurement of the ability of an electron to attract another electron

QUESTION POSTED AT 01/06/2020 - 03:50 PM

### Which of the following is not used to determine the brightness of a star? a) How far away the star is b) The size of the star c) The location of the star in the night sky d) How much light the star is giving off

QUESTION POSTED AT 01/06/2020 - 03:49 PM

### An engineer chooses to use a natural adhesive for a building project instead of a heavy-duty chemical glue that releases harmful fumes. This is an example of _____. A. efficiency in construction B. cost-saving construction C. resource shortages D. green design is somebody out there that can help

QUESTION POSTED AT 01/06/2020 - 03:42 PM

### In which device is chemical energy transformed into electrical energy? A battery B hair dryer C television D hydroelectric plant

QUESTION POSTED AT 01/06/2020 - 03:40 PM