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2 years ago

Why do you think the molarity relationship is so important to the chemist?

1 answer:

5 0

There are two big advantages of using molarity to express concentration. The first advantage is that it's easy and convenient to use because the solute may be measured in grams, converted into moles, and mixed with a volume.

The second advantage is that the sum of the molar concentrations is the total molar concentration. This permits calculations of density and ionic strength

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Describe the shapes and relative energies of the s,p,d, and f atomic orbitals?

Mariulka [41]

Relative energies are in the order:

s < p < d < f

And the shape of these orbitals are

s - spherical

p - dumbbell

d - double dumbbell

f - double double dumbbell

6 0

2 years ago

Read 2 more answers

The reaction nacl(s) → nacl(aq) is performed in a coffee cup calorimeter, using 100 ml of h2o(l) and 5.00g of nacl. if the tempe

MrRissso [65]

Since the density of water is 1 g /mL, hence there is 100 g of H2O. So total mass is:

m = 100 g + 5 g = 105 g

=> The heat of reaction can be calculated using the formula:

δhrxn = m C ΔT

where m is mass, C is heap capacity and ΔT is change in temperature = negative since there is a decrease

δhrxn = 105 g * 4.18 J/g°C * (-2.30°C)

δhrxn = -1,009.47 J

=> However this is still in units of J, so calculate the number of moles of NaCl.

moles NaCl = 5 g / (58.44 g / mol)

moles NaCl = 0.0856 mol

=> So the heat of reaction per mole is:

δhrxn = -1,009.47 J / 0.0856 mol

δhrxn = -11,798.69 J/mol = -11.8 kJ/mol

5 0

2 years ago

Cracking the periodic table code why aren't the elements listed in alphabetical order answer key

finlep [7]

The elements in the periodice table are not listed in alphabetical order, because the arragement in rows (periods) and columns (groups or familes), in increasing order of atomic number (number of protons of the atoms) permits to explain similarities among the elements, trend in some properties, and even predict properties of unknown elements.

For example, the elements of the first group (family), called alkaline metals, all have 1 valence electron, have similar physical properties (ductibility, malleability, luster, thermal and electricity conductivity), react in similar way with water, show a trend in the atomic radii and in the ionization energy.

You can tell similar stories for other groups like, alkalyne earth metals, halogens and noble gases.

You can also tell trends in electroneativities, and atomic radii, for a row of elements, as per the order they are in the row.

So, the current array resulted very helpul for chemists to explain and predict the behavior and properties of the elements.

4 0

2 years ago

Read 2 more answers

How does convection affect the earths atmosphere

mel-nik [20]

Answer:

I think the layers of the atmosphere does temperature increase with increasing height. It is affected by convection because it heats the lower atmosphere. It is affected by conduction because the is the transfer of thermal energy. I guess

Hope this help!

3 0

1 year ago

antimony has two naturally occuring isotopes, sb121sb121 and sb123sb123 . sb121sb121 has an atomic mass of 120.9038 u120.9038 u

Luda [366]

Considering the definition of atomic mass, isotopes and atomic mass of an element, sb121 has a percent natural abundance of 0.5726 or 57.26% and sb123 has a percent natural abundance of 0.4284 or 42.84%.

<h3>Definition of atomic mass</h3>

The atomic mass is obtained by adding the number of protons and neutrons in a given nucleus of a chemical element.

<h3>Definition of isotope</h3>

Isotopes are the chemical elements in which atomic numbers are the same, but the number of neutrons is different.

<h3>Definition of atomic mass</h3>

The atomic mass of an element is the weighted average mass of its natural isotopes.

This is, the atomic masses of elements are usually calculated as the weighted average of the masses of the different isotopes of each element, considering the relative abundance of each of them.

<h3>Percent natural abundance of each isotope</h3>

In this case, antimony has two naturally occuring isotopes, sb121 and sb123. You know:

sb121 has an atomic mass of 120.9038 u.
sb121 has a percent natural abundance of x.
sb123 has an atomic mass of 122.9042 u.
sb123 has a percent natural abundance of 1 -x (or, what is the same, the abundance is 100% - x%, since both isotopes form 100% of the element.)
Antimony has an average atomic mass of 121.7601 u