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4 years ago

Molecules are the smallest units of matter with the characteristic properties of a substance.

1 answer:

3 0

False, Atoms are the smallest units of matter that display both the chemical and physical properties of it, based on the structure of the atom.

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Copper has two naturally occurring isotopes, ⁶³Cu (isotopic mass = 62.9296 amu) and ⁶⁵Cu (isotopic mass = 64.9278 amu). If coppe

Stells [14]

Copper has two naturally occurring isotopes, ⁶³Cu (isotopic mass = 62.9296 amu) and ⁶⁵Cu (isotopic mass = 64.9278 amu). If copper has an atomic mass of 63.546 amu,

Abundance of ⁶³Cu and ⁶⁵Cu ; 70% , 30.848%

<h3>Calculation : </h3>

Let the natural abundance of 63, Cu isotope be x%.

The natural abundance of

Cu isotope will be 100−x.

The average atomic weight is 63.546 g.

Hence, 100×63.546=63x+65(100−x)

6354.6=63x+6500−65x=6500−2x

2x=145.4

x=72.7≃70

Hence, the natural abundance of the 63Cu isotope must be approximately 70%.

For the ⁶⁵Cu calculation is same and the answer is 30.848%

<h3>What is isotope ?</h3>

Isotopes are members of a family of elements that all have the same number of protons and different numbers of neutrons. The number of protons in the nucleus determines the atomic number of an element on the periodic table.

Example : Magnesium has three natural isotopes : ²⁴Mg, ²⁵Mg, and ²⁶Mg.

<h3>What is Atomic mass ?</h3>

Atomic mass is the mass of an atom. The SI unit of mass is the kilogram, while atomic mass is often expressed in the non-SI unit dalton (synonymous with uniform atomic mass unit). 1 Da is defined as 1/12 the mass of a free carbon-12 atom at rest in the ground state.

To know more about Atomic mass please click here : brainly.com/question/338808

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3 0

1 year ago

Harvey kept a balloon with a volume of 348 milliliters at 25.0˚C inside a freezer for a night. When he took it out, its new volu

ad-work [718]

Initial volume of the balloon = $V_{1}$ = 348 mL

Initial temperature of the balloon $T_{1}$ = $25.0^{0}C + 273 = 298 K$

Final volume of the balloon $V_{2}$ = 322 mL

Final temperature of the balloon = $T_{2} = ?$

According to Charles law, volume of an ideal gas is directly proportional to the temperature at constant pressure.

$\frac{V_{1} }{T_{1} } =\frac{V_{2} }{T_{2} }$

On plugging in the values,

$\frac{348mL}{298 K} =\frac{322 mL}{T_{2} }$

$T_{2} =276 K$

Therefore, the temperature of the freezer is 276 K

5 0

3 years ago

Italian dressing contains olive oil and vinegar, which will separate out from each other if left to sit. This makes the dressing

OleMash [197]

Italian salad dressing would be a suspension

6 0

2 years ago

Which of the following is NOT true of white dwarfs?

liq [111]

Answer:

A white dwarf is what stars like the Sun become after they have exhausted their nuclear fuel. Near the end of its nuclear burning stage, this type of star expels most of its outer material, creating a planetary nebula. Only the hot core of the star remains. ... That means a white dwarf is 200,000 times as dense.

Explanation:

they are cold

they are about the size of Earth

these both are not true

6 0

3 years ago

Read 2 more answers

Calculate the density of nitrogen gas, in grams per liter, at stp.

lesantik [10]

Standard temperature is 273 K

Standard pressure is 1 atm

We use the ideal gas equation to find out density of nitrogen gas in g/L

Ideal gas equation:

$PV = nRT\\ PV = (\frac{Mass}{Molar mass)}RT\\ P(Molar mass) = (\frac{Mass}{Volume})RT\\ \frac{Mass}{Volume}=\frac{P(molar mass)}{RT} \\ Density = \frac{P(Molar mass)}{RT}$

Molar mass of $N_{2} = 28 g/mol$

Pressure = 1 atm

Temperature = 273 K

$Density = \frac{(1atm)(28 g/mol)}{(0.08206 \frac{L.atm}{mol.K})(273 K)}$

= 1.25 g/L

Therefore, density of nitrogen gas at STP is 1.25 g/L

4 0

3 years ago