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Anuta_ua [19.1K]
3 years ago
6

6. What is the total number of calories lost when 10

Chemistry
1 answer:
Nadusha1986 [10]3 years ago
3 0

Answer:

B

Explanation:

so you started out with 80

you have to cool it till 60

so it is decreasing which means you have to subtract

Note=if something is increasing or wanting to go up its addition but for this problem 60 is less then 80 so we are doing subtraction

80-60=20

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AleksAgata [21]
The answer is punnet square
3 0
2 years ago
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How many reactant molecules and product gas molecules are in this equation?
Mice21 [21]

Answer:

N₂  = 6.022 × 10²³ molecules

H₂ = 18.066 × 10²³ molecules

NH₃ = 12.044 × 10²³ molecules

Explanation:

Chemical equation;

N₂ + 3H₂     →  2NH₃

It can be seen that there are one mole of nitrogen three mole of hydrogen and two moles of ammonia are present in this equation. The number of molecules of reactant and product would be calculated by using Avogadro number.

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

Number of molecules of nitrogen gas:

1 mol = 6.022 × 10²³ molecules

Number of molecules of hydrogen:

3 mol × 6.022 × 10²³ molecules/ 1 mol

18.066 × 10²³ molecules

Number of molecules of ammonia:

2 mol × 6.022 × 10²³ molecules/ 1 mol

12.044 × 10²³ molecules

6 0
3 years ago
An unknown compound displays singlets at δ 2.1 ppm and 2.56 ppm in the ratio of 3:2. what is the structure of the compound?
olasank [31]

1) As can be seen from any 1H NMR chemical shift ppm tables, hydrogens which have δ values from 2ppm to 2.3ppm are hydrogens from carbon which is bonded to a carbonyl group. From this, we can conclude that our hydrogens belong to the type, but from 2 different alkyl groups because of 2 different signals.

 

2) So, one alkyl group is CH3 and second one can be CH or CH2.

 

3) If we know that ratio between two types of hydrogens is 3:2, it can be concluded that second alkyl group is CH2. 


4) Finally, we don't have any other signals and it indicates that part of the compound which continues on CH2 is exactly the same as the first part.

The ratio remains the same, 3:2 ie 6:4

7 0
3 years ago
Is photosphere the layer that emits sunlight?​
weqwewe [10]

Answer:

In our Sun, as in other stars, roughly 99.9% or so of all light emitted is emitted in a thin layer known as the photosphere, or light sphere. This is explained as follows. Interior to the photosphere the gas is ever denser and becomes far too opaque for any photon to emerge directly from that layer.

Explanation:

4 0
3 years ago
Read 2 more answers
An ideal gas sealed in a rigid 4.86-L cylinder, initially at pressure Pi=10.90 atm, is cooled until the pressure in the cylinder
seraphim [82]

Answer:

\Delta H=-11897J

Explanation:

Hello,

In this case, it is widely known that for isochoric processes, the change in the enthalpy is computed by:

\Delta H=\Delta U+V\Delta P

Whereas the change in the internal energy is computed by:

\Delta U=nCv\Delta T

So we compute the initial and final temperatures for one mole of the ideal gas:

T_1= \frac{P_1V}{nR}=\frac{10.90atm*4.86L}{0.082*n}=\frac{646.02K  }{n} \\\\T_2= \frac{P_2V}{nR}=\frac{1.24atm*4.86L}{0.082*n}=\frac{73.49K  }{n}

Next, the change in the internal energy, since the volume-constant specific heat could be assumed as ³/₂R:

\Delta U=1mol*\frac{3}{2} (8.314\frac{J}{mol*K} )*(73.49K-646.02K )=-7140J

Then, the volume-pressure product in Joules:

V\Delta P=4.86L*\frac{1m^3}{1000L} *(1.24atm-10.90atm)*\frac{101325Pa}{1atm} \\\\V\Delta P=-4756.96J

Finally, the change in the enthalpy for the process:

\Delta H=-7140J-4757J\\\\\Delta H=-11897J

Best regards.

7 0
3 years ago
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