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3 years ago

How do scientists use light-years?

Chemistry

1 answer:

sveticcg [70]3 years ago

8 0

Answer:

Scientists don't actually measure astronomical distances in light years. Rather, they measure them in a unit called the Parsec , and only convert to light years when they're talking to the general public . One light-year is the distance light travels through space in one year.

Explanation:

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What mass of naturally occurring uranium is closer to 238 u , 235 u or 234 u?

Liono4ka [1.6K]

Uranium (92U) is a naturally occurring radioactive element that has no stable isotopes but two primordial isotopes (uranium-238 and uranium-235) that have long half-life and are found in appreciable quantity in the Earth's crust, along with the decay product uranium-234.

7 0

3 years ago

Equal volumes of hydrogen and helium gas are at the same pressure. The atomic mass of helium is four times that of hydrogen. If

OverLord2011 [107]

Answer:

The ratio of the temperature of helium to that of hydrogen gas is 2:1.

Explanation:

Atomic mass of hydrogen = M

Temperature of hydrogen gas =T

Pressure of the hydrogen gas = P

Mass of the hydrogen gas = m

Moles of the hydrogen gas = $n=\frac{m}{2M}$

Volume of the hydrogen gas = V

Using an ideal gas equation:

$PV=nRT=PV=\frac{mRT}{M}$ ...(1)

Temperature of helium gas =T'

Pressure of the helium gas = P'= P

Mass of the helium gas = m' =m

Moles of the helium gas = $n'=\frac{m}{M'}=\frac{m}{4M}$

Volume of the helium gas = V' = V

Using an ideal gas equation:

$P'V'=n'RT'=\frac{mRT'}{4M}$ ...(2)

Divide (2) by (1)

$\frac{P'V'}{PV}=\frac{\frac{mRT'}{4M}}{\frac{mRT}{2M}}$

$\frac{T'}{T}=\frac{2}{1}$

The ratio of the temperature of helium to that of hydrogen gas is 2:1.

7 0

3 years ago

A student made the Lewis dot diagram of a compound as shown.

Svetradugi [14.3K]

Answer:

Both electrons of Mg should be transferred to one O.

Explanation:

This is because metals like to lose electrons whereas non metals like to gain electrons in an ionic compound. MgO is an ionic compounds. So Magnesium being a metal in group 2 of periodic table, it wants to donate 2 electrons to get to the octet rule, so it donates its electrons and oxygen accepts them to fill its octet rule.

4 0

3 years ago

Read 2 more answers

How many moles of Na₂CO₃ required to create 9.54 liters of a 3.4 M solution

GarryVolchara [31]

Answer:

The answer to your question is 32.44 moles

Explanation:

Data

moles of Na₂CO₃ = ?

volume = 9.54 l

concentration = 3.4 M

Formula

Molarity = $\frac{number of moles}{volume}$

Solve for number of moles

number of moles = Molarity x volume

Substitution

Number of moles = (3.4)( 9.54)

Simplification

Number of moles = 32.44

3 0

3 years ago

Read 2 more answers

Is this Physical or Chemical change?

ryzh [129]

This is chemical change

8 0

4 years ago