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3 years ago

True or false. a wheel and axle are a rotating lever that move around an effort arm?

Chemistry

1 answer:

adelina 88 [10]3 years ago

7 0

Answer:

True

Explanation:

the machine shown in figure 9.9 is called a wheele and axle. It's a form of lever. the effort arm can rotate in a complete circle, which is the center of the axle.

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The average propane cylinder for a residential grill holds approximately 18 kg of propane. How much energy (in kJ) is released b

brilliants [131]

Combustion is a chemical reaction between a fuel and an oxidant, oxygen, to give off combustion products and heat. Complete combustion results when all of the fuel is consumed to form carbon dioxide and water, as in the case of a hydrocarbon fuel. Incomplete combustion results when insufficient oxygen reacts with the fuel, forming soot and carbon monoxide.

The complete combustion of propane proceeds through the following reaction:
$C_{3} H_{8}$ + $5O_{2}$ --> $3CO_{2}$ + $4H_{2}O$

Combustion is an exothermic reaction, which means that it gives off heat as the reaction proceeds. For the complete combustion of propane, the heat of combustion is (-)2220 kJ/mole, where the minus sign indicates that the reaction is exothermic.

The molar mass of propane is 44.1 grams/mole. Using this value, the number of moles propane to be burned can be determined from the mass of propane given. Afterwards, this number of moles is multiplied by the heat of combustion to give the total heat produced from the reaction of the given mass of propane.

14.50 kg propane x 1000 g x 1 mole propane x 2220 kJ 
1 kg 44.1 g 1 mole

= 729,931.97 kJ

8 0

3 years ago

The pOH of a solution is 9.21. Calculate the hydrogen ion concentration of the solution. Be sure to report your answer to the co

11Alexandr11 [23.1K]

Answer:

[OH-] = 6.17 *10^-10

Explanation:

Step 1: Data given

pOH = 9.21

Step 2: Calculate [OH-]

pOH = -log [OH-] = 9.21

[OH-] = 10^-9.21

[OH-] = 6.17 *10^-10

Step 3: Check if it's correct

pOH + pH = 14

[H+]*[OH-] = 10^-14

pH = 14 - 9.21 = 4.79

[H+] = 10^-4.79

[H+] = 1.62 *10^-5

6.17 * 10^-10 * 1.62 * 10^-5 = 1* 10^-14

3 0

3 years ago

Choose the answer below that gives the correct chemical symbol and classification (metal, metalloid, or nonmetal) for the elemen

Zielflug [23.3K]

Answer: B. The element called tin is a metal with the chemical symbol Sn.

Explanation:

A is incorrect because Ni is Nickel, not Niobium.

C is incorrect because Carbon is a nonmetal and its symbol is C, not Cr.

D is incorrect because Copper's symbol is Cu, not Ce.

E is incorrect because As is the symbol for Arsenic, not Astatine.

6 0

3 years ago

HELLLLLLPPPPPP ME NOW I WILL GIVE YA THE BRAINLIEST ANSWER WHOEVER ANSWERS FIRSTTTTTTT

denis23 [38]

Answer:

I think acetone has more because water is just H20

5 0

3 years ago

Read 2 more answers

Which parts of LED bulb needs to stay cool as well as which part must transfer energy away from the diode???

storchak [24]

Answer:

every method of removing heat from LED's should be considered. Conduction, convection, and radiation are the three means of heat transfer. Typically, LED's are encapsulated in a transparent resin, which is a poor thermal conductor. Nearly all heat produced is conducted through the back side of the chip. Heat is generated from the PN junction by electrical energy that was not converted to useful light, and conducted to outside ambiance through a long path, from junction to solder point, solder point to board, and board to the heat sink and then to the atmosphere. A typical LED side view and its thermal model are shown in the figures.

Explanation:

6 0

3 years ago