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Julli [10]
3 years ago
15

A hot air balloon of 257m^3 is made from 8.50kg of materials. The outside atmosphere is 1.00 atm, and 18C and pure N2 atmosphere

.
CH4 + 2 O2 --> CO2 + 2H2O dHrxn = -890 kJ
All heat from CH4 burning goes into all the air originally in the balloon before heating
SN2 = 0.55 J/gC

What mass in grams of CH4 needed to be burned to achieve neutral buoyancy?
Chemistry
1 answer:
Ulleksa [173]3 years ago
4 0

Answer:

2.87

Explanation:

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Please help me!!!!!!!!
Oksanka [162]
Your answer would be surface runoff 
5 0
3 years ago
2.3 Zinc has five naturally occurring isotopes: 48.63% of 64 Zn with an atomic weight of 63.929 amu; 27.90% of 66Zn with an atom
lakkis [162]

<u>Answer:</u> The average atomic mass of element Zinc is 65.40 amu.  

<u>Explanation:</u>

Average atomic mass of an element is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.

Formula used to calculate average atomic mass follows:

\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i .....(1)

  • <u>For _{30}^{64}\textrm{Zn} isotope:</u>

Mass of _{30}^{64}\textrm{Zn} isotope = 63.929 amu

Percentage abundance of _{30}^{64}\textrm{Zn} isotope = 48.63 %

Fractional abundance of _{30}^{64}\textrm{Zn} isotope = 0.4863

  • <u>For _{30}^{66}\textrm{Zn} isotope:</u>

Mass of _{30}^{66}\textrm{Zn} isotope = 65.926 amu

Percentage abundance of _{30}^{66}\textrm{Zn} isotope = 27.90 %

Fractional abundance of _{30}^{66}\textrm{Zn} isotope = 0.2790

  • <u>For _{30}^{67}\textrm{Zn} isotope:</u>

Mass of _{30}^{67}\textrm{Zn} isotope = 66.927 amu

Percentage abundance of _{30}^{67}\textrm{Zn} isotope = 4.10 %

Fractional abundance of _{30}^{67}\textrm{Zn} isotope = 0.0410

  • <u>For _{30}^{68}\textrm{Zn} isotope:</u>

Mass of _{30}^{68}\textrm{Zn} isotope = 67.925 amu

Percentage abundance of _{30}^{68}\textrm{Zn} isotope = 18.75 %

Fractional abundance of _{30}^{68}\textrm{Zn} isotope = 0.1875

  • <u>For _{30}^{70}\textrm{Zn} isotope:</u>

Mass of _{30}^{70}\textrm{Zn} isotope = 69.925 amu

Percentage abundance of _{30}^{70}\textrm{Zn} isotope = 0.62 %

Fractional abundance of _{30}^{70}\textrm{Zn} isotope = 0.0062

Putting values in equation 1, we get:

\text{Average atomic mass of Zinc}=[(63.929\times 0.4863)+(65.926\times 0.2790)+(66.927\times 0.0410)+(67.925\times 0.1875)+(69.925\times 0.0062)]

\text{Average atomic mass of Zinc}=65.40amu

Hence, the average atomic mass of element Zinc is 65.40 amu.

7 0
3 years ago
What happens to the mass of substances during a physical change?
Anna [14]

Here are the answers in order:

1. During a physical change the substance changes physically.

2. The law of conservation of mass is a law stating the conservation of mass cannot be higher than 46mg or lower than 32mg.

3. A hypothesis is a guess that you make before completing a science experiment, it can be considered a law because it is important to know why you are making the guess.

4. During a chemical change the mass is changing colors. This is a representation of a chemical change.

5. Oil is a non-renewable resource, so it cannot demonstrate the conservation of mass.

6. When the color of the substance has changed or when it explodes.

7. Reactants are the objects that react when in a chemical change.

8. If you follow the rule of not going higher than 46mg and not lower than 32mg then it will automatically follow this law.

Chemical Reactions Part One Video:

1. mass

2. erupt-ant

3. reactant

4. object

5. mixtures

6. molecules

7. color changed

Questions again:

1. A chemical reaction

2. A physical change

3. Because if it is no higher than 46mg and no lower than 32mg then it will follow on it's own.

8 0
3 years ago
Read 2 more answers
1. Describe the difference between an electron and a proton in terms of their charge.​
Zarrin [17]

Explanation:

Protons have a positive charge. Electrons have a negative charge. The charge on the proton and electron are exactly the same size but opposite. Neutrons have no charge.

5 0
2 years ago
Which is the least dense?<br><br> copper<br><br> mercury<br><br> water<br><br> wood
tamaranim1 [39]
Least dense means the one that is at the top. Wood floats on top of water, so wood would be the least dense. Water has a density of 1 and the others would all sink, so they're more dense. The answer is wood
4 0
3 years ago
Read 2 more answers
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