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3 years ago

How do we measure the mass of an extrasolar planet?

1 answer:

4 0

To determine a planet's mass, astronomers typically measure the minuscule movement of the star caused by the gravitational tug of an orbiting planet. For planets the massof Earth detecting such a tiny tug is extraordinarily challenging with current technology

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The mass of an atom is measured in a unit named the<br> ____. fill in the blank please helpppp

Volgvan

Answer: amu

Explanation: it stands for atomic mass unit and it is the measurement that’s used to measure the mass of atoms

5 0

3 years ago

The vapor pressure of water at 25.0°C is 23.8 torr. Determine the mass of glucose (molar mass = 180 g/mol) needed to add to 500.

mrs_skeptik [129]

According to Raoult's law the relative lowering of vapour pressure of a solution made by dissolving non volatile solute is equal to the mole fraction of the non volatile solute dissolved.

the relative lowering of vapour pressure is the ratio of lowering of vapour pressure and vapour pressure of pure solvent

$\frac{p^{0-}p}{p^{0}}=x_{B}$

Where

xB = mole fraction of solute=?

$p^{0}=23.8torr$

p = 22.8 torr

$x_{B}=\frac{23.8-22.8}{23.8}=0.042$

mole fraction is ratio of moles of solute and total moles of solute and solvent

moles of solvent = mass / molar mass = 500 /18 = 27.78 moles

putting the values

$molefraction=\frac{molessolute}{molesolute+molessolvent}$

$0.042=\frac{molessolute}{27.78+molessolute}$

$1.167+0.042(molesolute)=molessolute$

$molessolute=1.218$

mass of glucose = moles X molar mass = 1.218 X 180 = 219.24 grams

3 0

3 years ago

Calculate Ho298 for the process

Inga [223]

Explanation:

As per the Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

Hence, according to this law the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

$Sb + \frac{3}{2}Cl_2 \rightarrow SbCl_{3}$ $\Delta H^0_1 = -314 kJ$ ..........(1)

$SbCl_{3} + Cl_2 \rightarrow SbCl_{5}$ $\Delta H^0_2 = -80kJ$ ..............(2)

The final reaction is as follows:

$Sb + \frac{5}{2}Cl_{2} \rightarrow SbCl_{5}$ $\Delta H^0_3 = ?$ .............(3)

Therefore, adding (1) and (2) we get the final equation (3) and value of $\Delta H^{0}_{3}$ at 298 K will be as follows.

$\Delta H^{0}_{3}$ = $\Delta H^{0}_{1}$ + $\Delta H^{0}_{2}$

= -314 kJ + (-80) kJ

= -394 kJ

Thus, we can conclude that $H^{o}$ at 298 K for the given process is -394 kJ.

4 0

3 years ago

How many moles are equal to 2.188E+23 atoms of iron?

rusak2 [61]

<span>2.188*10^23 atoms of iron
6.022*10^23 atoms/mole
(2.188*10^23 atoms of iron)/(6.022*10^23 atoms/mol)~.3633 moles of iron

Hope this helps!</span>

7 0

3 years ago

Why can it be difficult to demonstrate the Law of Conservation of Mass in action when a chemical reaction takes place in an open

rjkz [21]

Answer:

In simple words, in an open system, the system that has external interactions. Such interactions can take the form of information, energy, mass etc. So keeping this definition in mind, the law of conservation of mass in open system is difficult because when chemical reaction takes places things change form and some things are released as energy, That energy than escapes the system and interacts with other surrounding. This is why it is difficult to demonstrate Law of Conservation of Mass because the changes in mass due to chemical reaction cannot be accounted for properly since the lost mass (in form of energy) was lost to environment.

Whereas, in closed system, all components occur inside a closed container or something where external interactions are minimal to none so the energy lost due to chemical reaction does not escape the system thus it can be accounted for properly to demonstrate the law of conservation of Mass.

Explanation:

Too many words but should get the point across hopefully!

3 0

3 years ago