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3 years ago

is there a difference between a homogenouos mixture of hydrogen gas and oxygen gas, and a sample of vapor? explain?

1 answer:

8 0

Yes. In a homogeneous mixture the hydrogen and oxygen are not chemically combined; in water vapor, they are. You can separate a homogeneous mixture of hydrogen and oxygen by physical means, such as by cooling the mixture until the oxygen liquefies. If you cool water vapor you're just going to get liquid water and then ice - not two separate substances. That's because compounds can only be separated into their elements by chemical means.

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The diagram below shows the branching tree diagram for humans. The text box below it shows the set of derived shared characteris

pentagon [3]

Answer:

I would write "terrestrial/lives on land during all life stages" between the frog and pigeon branches

Explanation:

Jaw evolution has started with fish, so i'd place that before the perch, evolution of four limbs is next and I would plate it between the perch and the frog. Evolution of an egg has ensured that organisms remain terrestrial during all stages of life and don't need to rely on water to lay their eggs. So I would place that between the frog and the pigeon. True mammary glands and true hair, as we know it formed on mammals so i'd place that between the pigeon and the rats (although synapsids evolved similar structures long before birds even existed). And lastly, I would place "walking on two legs" between rats and human branches. Because our ancestors evolved bipedalism relatively late.

6 0

2 years ago

If the mass is 6.5g, and the volume is 25mL.. what is the density? PLEASE ANSWER ASAP

julia-pushkina [17]

Answer:

p = 260 kilogram/cubic meter

Explanation:

ρ = $\frac{m}{V} \\$

= $\frac{6.5 g}{25mL}$

= 0.26 gram/milliliter

= 260 kilogram/cubic meter

7 0

3 years ago

It is proposed to use Liquid Petroleum Gas (LPG) to fuel spark-ignition engines. A typical sample of the fuel on a volume basis

Norma-Jean [14]

Answer:

The overall balanced combustion reaction is written as :

$0.7C_3H_8 \ + \ 0.05C_4H_{10} \ + \ 0.25 C_3H_6 \ + \ x(O_2 \ + \ 3.76N_2) ---> 3.05CO_2 \ + \ 3.8H_2O \ + \ 18.612N_2$

$(F/A)_{stoichiometric} = 0.0424$

$(A/F)_{stoichiometric} = 23.562$

the higher heating values $(HHV)_f$ per unit mass of LPG = 49.9876 MJ/kg

the lower heating values $(LHV)_f$ per unit mass of LPG = 46.4933 MJ/kg

Explanation:

The stoichiometric equation can be expressed as :

$0.7C_3H_8 \ + \ 0.05C_4H_{10} \ + \ 0.25 C_3H_6 \ + \ x(O_2 \ + \ 3.76N_2) ---> aCO_2 \ + \ bH_2O \ + \ cN_2$

Now, equating the coefficient of carbon; we have:

(0.7×3)+(0.05×4)+(0.25×3) = a

a = 3.05

Also, Equating the coefficient of hydrogen : we have:

(0.7 × 8) +(0.05 × 10) + ( 0.25 × 6) = 2 b

2b = 7.6

b = 3.8

Equating the coefficient of oxygen

2x = 2a + b

$x = \frac{2a+b}{2} \\ \\ x = \frac{2(3.05)+3.8}{2} \\ \\ x = 4.95$

Equating the coefficient of Nitrogen

$c = 3.76x \\ \\ c = 3.76 *4.95 \\ \\ c = 18.612$

Therefore, The overall balanced combustion reaction can now be written as :

$0.7C_3H_8 \ + \ 0.05C_4H_{10} \ + \ 0.25 C_3H_6 \ + \ x(O_2 \ + \ 3.76N_2) ---> 3.05CO_2 \ + \ 3.8H_2O \ + \ 18.612N_2$

Now; To determine the stoichiometric F/A and A/F ratios; we have:

$(F/A)_{stoichiometric} = \frac{n_f}{n_a } \\ \\ (F/A)_{stoichiometric} = \frac{1}{4.95*(1+3.76)} \\ \\ (F/A)_{stoichiometric} = 0.0424$

$(A/F)_{stoichiometric} = \frac{n_a}{n_f } \\ \\ (A/F)_{stoichiometric} = \frac{4.95*(1+3.76)}{1} \\ \\ (A/F)_{stoichiometric} = 23.562$

What are the higher and lower heating values per unit mass of LPG?

Let calculate the molecular mass of the fuel in order to determine their mass fraction of the fuel components.

Molecular mass of the fuel $M_f = (0.7*M_{C_3H_5} ) + (0.05 *M_{C_4H_{10}}) + (0.25*M _{C_3H_6})$

= 30.8 + 2.9 + 10.5

= 44.2 kg/mol

Mass fraction of the fuel components can now be calculated as :

$m_{C_3H_8} = \frac{30.8}{44.2} \\ \\ m_{C_3H_8} = 0.7 \\ \\ \\ m_{C_4H_{10}} = \frac[2.9}{44.2} \\ \\ m_{C_4H_{10}} = 0.06 \\ \\ \\ m_{C_3H_6} = \frac{10.5}{44.2} \\ \\ m_{C_3H_6} = 0.24$

Finally; calculating the higher heating values $(HHV)_f$ per unit mass of LPG; we have:

$(HHV)_f=(0.7 * HHV_{C_3H_8}) + (0.06 *HHV_{C_4H_{10}})+(0.24*HHV_{C_3H_6} \\ \\ (HHV)_f=(0.7*50.38)+(0.06*49.56)+(0.24*48.95) \\ \\ (HHV)_f=49.9876 \ MJ/kg$

calculating the lower heating values $(LHV)_f$ per unit mass of LPG; we have:

$(LHV)_f = (HHV)_f - \delta H_w \\ \\ (LHV)_f = (HHV)_f - [\frac{m_w}{m_f}h_{vap}] \\ \\ (LHV)_f = 49.9876 \ MJ/kg - [\frac{3.8*18}{44.2}*2.258 \ MJ/kg] \\ \\ (LHV)_f = 46.4933 \ M/kg$

7 0

3 years ago

Electromagnetic radiation with a wavelength of 575 nm appears as yellow light to the human eye. The energy of one photon of this

Alecsey [184]

Answer:

9.12 * 10^20 photons

Explanation:

Given that;

E=n⋅h⋅ν

Where;

E= energy of the electromagnetic radiation

n = number of photons

h = Plank's constant

ν = frequency of electromagnetic radiation

Hence;

n = E/hν

n = 3.46 × 10 -19/6.6 * 10^-34 * 575 * 10^-9

n = 3.46 × 10 -19/3795 * 10^-43

n= 9.12 * 10^20 photons

7 0

2 years ago

I NEED HELP ASAP PLEASE

scZoUnD [109]

I think it’d be C. I’m not 100% if it is tho

8 0

3 years ago