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3 years ago

if a 2.0g sample of water at 5.0celcius absorbs 21.8Joules of energy, the temprature of the sample will be raised by

1 answer:

8 0

You'd use the temperature change equation. The specific heat of water is always 4.18J/(g °C).
Equation to use: q=mCΔT

21.8=(2.0)(4.18)(Tf-5)
21.8=(8.36)(Tf-5)
21.8/8.36=Tf-5
2.61=Tf-5
2.61+5=Tf
Tf=7.61 °C

Since you want to know how many °C it raises, you wouldn't pay attention to the last 2 steps, however if you need to know the final temp, you want to go to the last step.

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Consider the reaction of 19.0 g of zinc metal with excess silver nitrate to produce silver metal and zinc nitrate. The reaction

Alexeev081 [22]

Answer:

14.5 g silver

Explanation:

This is a problem using the stoichiometry of the reaction. First thing we need is the balanced equation:

Zn + 2 AgNO3 ----------------------- 2 Ag + Zn(NO3)2

We know that 14.6 g of Zn did not reacted, then we can calculate the amount of Zn reacted and do the calculation given the above reaction.

amount Zn reacted: 19.0 -14.6 g Zn = 4.4 g Zn

atomic weight of Zn: 65.37 g/mol

mol Zn reacted: 4.4 g Zn x ( 1 mol Zn/ 65.37 g Zn) = 0.067 mol Zn

We know from the balanced equation that moles of Ag are produced from 1 mol Zn therefore the mol of Ag produced are:

0.067 mol Zn x 2 mol Ag/ 1mol Zn = 0.135 mol Ag

and the mass of silver then will be given by multiplying by the atomic weight of silver:

0.135 mol Ag x 107.9 g/mol = 14.5 g Ag

4 0

3 years ago

A balloon is filled with 6.5 L of helium gas at 25oC and 1.0 atm. What volume will the balloon have when the temperature is lowe

harkovskaia [24]

Figure it out yet ?????

5 0

3 years ago

How to balance barium and oxygen yield barium oxide

olga55 [171]

Barium : $Ba^{+2}$ with +2 being the charge
Oxygen : $O^{-2}$ with -2 being the charge

The given equation can be written as:
Ba + O = BaO

Since the sum charges of Barium and Oxygen equals 0, there is no need to add subscripts.

Both Ba and O appear on the left and right side of the equation once, so there is no need to add a coefficient.

Ba + O = BaO is balanced

4 0

3 years ago

Ammonia can also be synthesized by the reaction 3h2(g)+n2(g)→2nh3(g) what is the theoretical yield of ammonia, in kilograms, tha

dalvyx [7]

We are given the complete reaction:

First let us convert mass to moles.

moles H2 = 5.22 kg / (2 kg/kmol) = 2.61 kmol H2

moles N2 = 31.5 kg / (28 kg/kmol) = 1.125 kmol N2

Then we find for the limiting reactant. The limiting reactant is the one who has lower (moles/coefficient) ratio.

H2 = 2.61 / 3 = 0.87

N2 = 1.125 / 1 = 1.125

Hence the H2 is the limiting reactant so we should base the calculation of NH3 from it. We see that 2 moles of NH3 is produced for every 3 moles of H2, therefore:

moles NH3 = 2.61 kmol H2 * (2 kmol NH3 / 3 kmol H2) = 1.74 kmol

The molar mass of NH3 is 17 kg/kmol, therefore the mass NH3 is:

mass NH3 = 1.74 kmol * 17 kg/kmol

4 0

3 years ago

Read 2 more answers

1. How does the amount of energy in the batteries in a flashlight compare to the total amount of energy given off by the flashli

qaws [65]

1. The total energy in the batteries and the total energy given off by the flashlight through heat and light is equal. This is because of the "Law of the Conservation of Energy." Energy cannot be created or destroyed, only changed in form. This can also be backed with the first law of thermodynamics.

2. A rate of a chemical reaction can be increased by increasing the temperature, or introducing a catalyst.

3. a. The saliva acts as a catalysts in breaking down the cracker.

3. b. The energy is stored in the chemical bonds on the sugars in the cracker.

3. c. The energy is the cracker is released through the body's natural process in breaking down the cracker and the sugars.

5 0

3 years ago