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The Question & Answer (Q&A) Knowledge Managenet

The Internet has many places to ask questions about anything imaginable and find past answers on almost everything.

Table of Contents

- Is Delta H equal to Delta U?
- What does a negative delta V mean?
- How do you tell if Delta U is positive or negative?
- How is Delta-V calculated?
- Why is it called the ideal rocket equation?
- For which reaction is Delta H most nearly equal to Delta E?
- What is a good Delta E?
- What does it mean when E is positive?
- Is e 2x always positive?
- Can power of e be negative?
- What does e to the power mean?
- Is Delta a UW?
- Why does q mean heat?
- What does it mean if Q is positive?
- What does Q stand for in electricity?
- What is Q in heat transfer?

Reaction Involving Gases Most of the time these two are essentially equal. This is because most chemical changes involve minimal energy transfer in the form of work. Using these assumptions if there is no change in the number of moles of gas, then /(/Delta H = /Delta U/).

Delta V is the change in voltage over time. Negative delta v is when the cell’s voltage actually drops when it’s fully charged. 0 delta v is when it simply stops climbing in voltage when charged.

Adding onto the previous posts, if delta u is positive, then u(final) > u(initial). If delta u is negative, then u(final) < u(initial).

Change in velocity, or delta-V, is the most important measure of “distance” in space flight. To get from the ground to low Earth orbit (LEO) requires a delta-V of about 8600 m/sec. Specific Impulse is exhaust velocity divided by g, the acceleration due to gravity on Earth’s surface (9.80665 m/s^2).

The equation is named after Russian scientist Konstantin Tsiolkovsky (Russian: Константин Циолковский) who independently derived it and published it in his 1903 work. Robert Goddard in America independently developed the equation in 1912 when he began his research to improve rocket engines for possible space flight.

Liquids are generally incompressible, and so are solids. Thus, if the mols of gas don’t change, the volume of the system pretty much doesn’t change. Hence, we can say ΔH≈ΔE if Δngas=0 .

A Delta E between 3 and 6 is usually considered an acceptable number in commercial reproduction, but the color difference may be perceived by printing and graphic professionals. (Note: Human vision is more sensitive to color differences if two colors actually touch each other).

When the hot plate is turned on, the system gains heat from its surroundings. As a result, both the temperature and the internal energy of the system increase, and E is positive. When the hot plate is turned off, the water loses heat to its surroundings as it cools to room temperature, and. E is negative.

Solution. Since the value of e 2 x text is always positive for any real value of x, e 2 x > 0 .

The negative sign on an exponent means the reciprocal. Think of it this way: just as a positive exponent means repeated multiplication by the base, a negative exponent means repeated division by the base. So 2^(-4) = 1/(2^4) = 1/(2*2*2*2) = 1/16. The answer is 1/16.

But when used in displaying large or small numbers, e means “times ten to the power of…”. Keywords: e powers of ten, exponent.

Delta U is referred to as the change in internal energy of a system. Delta U is actually equal to q + w whereas q is the heat input or Delta H.

Use of the symbol Q for the total amount of energy transferred as heat is due to Rudolf Clausius in 1850: “Let the amount of heat which must be imparted during the transition of the gas in a definite manner from any given state to another, in which its volume is v and its temperature t, be called Q” .

Note: When heat is absorbed by the solution, q for the solution has a positive value. This means that the reaction produces heat for the solution to absorb and q for the reaction is negative.

q is the symbol used to represent charge, while n is a positive or negative integer, and e is the electronic charge, 1.60 x 10-19 Coulombs.

The letter Q represents the amount of heat transferred in a time t, k is the thermal conductivity constant for the material, A is the cross sectional area of the material transferring heat, Δ T /Delta T ΔT is the difference in temperature between one side of the material and the other, and d is the thickness of the …