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Levart [38]
3 years ago
13

7. Which statement about scientific consensus is true?

Chemistry
1 answer:
Helen [10]3 years ago
8 0
The answer is b, the only way to prove a theory true. Hope this helps :)
You might be interested in
Percent composition of a compound (molar mass= 60.06) 39.99% C, 6.727% H, 53.33% O, What is the molecular formula of the compoun
abruzzese [7]

You are calculating the empirical formula of this chemical compound, which is the question with moles, molar mass, and number of moles.

We assume the total mass of this compound is 100g. Because 39.99 +6.727+53.33 =100.047is about 100g. That's the easiest way for us to do it.

First you divide the mass of carbon by its molar mass(relative formula mass)because there is a formula about moles state: number of moles=mass/molar mass.

So, 40/12 is about 3.3. Then, the RFM of H is 1, so the number of mole is 6.7/1=6.7. The RFM of O is 16, whihc means the molar mass od oxygen is 16g, so 53.3/16, which is about 3.3 too.Next, you get the number of moles in order is; 3.3, 6.7, 3.3. Now we need to look at the ratio between these numbers. 3.3 and 3.3 has a common factor of 1, so the subscript of them are both 1. next use 6.7/3.3, and the greatest common factor is 2, so the empirical formula is CH2O.

BUT CH2O is only the empirical formula. what we need to do is calculate the RFM of CH2O first.

So, 12+2+16=30.

Then we find out how many times 30 goes into 60.06; 60.06/30 is 2.002. we simplify it as 2.

Finally, all the subscript need to times 2. therefore the molecular formula is C2H4O2.

To solve this kind of  questions, there are many steps:Know what you are calculating about, it's about the MOLECULAR formula, so you need to find out the number of moles of each elements, then the empirical formula, then the molecular formula.

) Find the RFM of the element, because that is the molar mass(mass of 1 mole) of this element.

2) number of moles= mass/molar mass. use this formula to help you get the number of moles of each element in this compound

3) look at the relationship between the number of moles of each elements. find out the ratio between them.

4)use the molar mass of the whole compound to find out the molecular formula of this compounds. calculate the RFM of the compound in empirical formula form, and then divide the molar mass by the RFM.

if i got anything wrong, please tell me :)



6 0
3 years ago
A hot-water stream at 70°C enters an adiabatic mixing chamber with a mass flow rate of 3.6 kg/s, where it is mixed with a stream
cupoosta [38]

Answer:

a) 4.58 kg/s

b) 0.105 kW/K

Explanation:

a) For the energy balance

qin = qout

min*cin*Tin = mout*cout*Tout

Where min is the mass flow that is entering the system, cin is the specific heat of the substance that is entering, Tin is the temperature of the substance that is entering, and the out is from the substances that are leaving the system. Because there is only water in the system cin = cout. The energy balance will be then:

mh*Th + mc*Tc = (mh + mc)*Tmix

Where h is from the hot water, c is from the cold water, and mix for the mixture that leaves the chamber. Th = 70ºC + 273 = 343 K, Tc = 20ºC + 273 = 293 K, Tmix = 42ºC + 273 = 315 K

3.6*343 + mc*293 = (3.6 + mc)*315

293mc - 315mc = 3.6*315 - 3.6*343

- mc*(315 - 293) = -3.6*(343 - 315)

mc = 3.6*(343 - 315)/(315 - 293)

mc = 3.6*28/22

mc = 4.58 kg/s

b) The entropy balance is:

Sin + Sout - Sgen = ΔSsystem

Where Sin is the entropy of the entering substances, Sout the entropy that the leaving substances, and Sgen the entropy that is generated in the process.

The entropy variantion for an adiabatic process is 0, so ΔSsystem = 0

Sgen = Sin + Sout

The sum of entropy is:

m*cp*ln(Tfinal/Tinitial), where cp is the specific heat (4.184 kJ/kg.K)

Sgen = mc*cp*ln(Tmix/Tc) + mh*cp*ln(Tmix/th)

Sgen = 4.58*4.184*ln(315/293) + 3.6*4.184*ln(315/343)

Sgen = 1.3874 + (-1.2827)

Sgen = 0.105 kW/K

5 0
3 years ago
PLEASE HELP WILL MARK BRAINLEST!!!!
puteri [66]

Answer: c????????

Explanation:

6 0
2 years ago
In the reaction aA + bB >> dD, the lowercase letters represent?
jolli1 [7]

Answer:

Coefficient

Explanation:

Chemical equation:

aA + bB    →   dD

This equation shows that reaction is balanced by coefficient q,b and d.

Reactant    coefficients              Product      Coefficient

A                    a                               D                     d

 B                    b                  

Every balanced equation follow the law of conservation of mass.

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

Explanation:

This law was given by french chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

For example:

In given photosynthesis reaction:

6CO₂ + 6H₂O + energy → C₆H₁₂O₆ + 6O₂

there are six carbon atoms, eighteen oxygen atoms and twelve hydrogen atoms on the both side of equation so this reaction followed the law of conservation of mass. The numbers 6 with CO₂, 6 with H₂O and 6 with O₂  are coefficient which balance the equation.

8 0
3 years ago
12. What did Darwin's ideas come to be known as? What is evolution?​
fomenos
Evolution of theory. Evolution is the process of how the people evolve
3 0
3 years ago
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