Which of the changes are physical changes

2.2 Chromium has four naturally-occurring isotopes: 4.34% of 50Cr, with an atomic weight of 49.9460 amu; 83.79% of 52Cr, with an

shutvik [7]

Answer:

Average atomic mass = 51.9963 amu

Explanation:

Given data:

Abundance of Cr⁵⁰ with atomic mass= 4.34% , 49.9460 amu

Abundance of Cr⁵² with atomic mass = 83.79%, 51.9405 amu

Abundance of Cr⁵³ with atomic mass =9.50%, 52.9407 amu

Abundance of Cr⁵⁴ with atomic mass = 2.37%, 53.9389 amu

Average atomic mass = 51.9963 amu

Solution:

Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass +....n) / 100

Average atomic mass = (4.34×49.9460)+(83.79×51.9405) +(9.50×52.9407)+ (2.37×53.9389) / 100

Average atomic mass = 216.7656 + 4352.0945 + 502.9367 +127.8352 / 100

Average atomic mass = 5199.632 / 100

Average atomic mass = 51.9963 amu

4 0

3 years ago

Can someone help me please

MArishka [77]

Answer:

Group 4A (or IVA) of the periodic table includes the nonmetal carbon (C), the metalloids silicon (Si) and germanium (Ge), the metals tin (Sn) and lead (Pb), and the yet-unnamed artificially-produced element ununquadium (Uuq).

The Group 4A elements have four valence electrons in their highest-energy orbitals (ns2np2). Carbon and silicon can form ionic compounds by gaining four electrons, forming the carbide anion (C4-) and silicide anion (Si4-), but they more frequently form compounds through covalent bonding. Tin and lead can lose either their outermost p electrons to form 2+ charges (Sn2+, the stannous ion, and Pb2+, the plumbous ion) or their outermost s and p electrons to form 4+ charges (Sn4+, the stannic ion, and Pb4+, the plumbic ion).

Carbon (C, Z=6).

Carbon is most familiar as a black solid is graphite, coal, and charcoal, or as the hard, crystalline diamond form. The name is derived from the Latin word for charcoal, carbo. It is found in the Earth's crust at a concentration of 480 ppm, making it the 15th most abundant element. It is found in form of calcium carbonate, CaCO3, in minerals such as limestone, marble, and dolomite (a mixture of calcium and

Explanation:

THIS ALL I KNOW

ENJOY THE ANSWER

3 0

3 years ago

Science question: Could you have seasons without revolution? Why or why not?

marusya05 [52]

Answer:

No

Explanation:

The Earth would not have seasons if there is no revolution because the temperatures would not change.

4 0

3 years ago

Why is the composition of Earth's atmosphere different from the composition of the atmospheres of Venus and Mars? A. Venus, Mars

rewona [7]

Answer:

they all have different chemical compositions from earth

Venus is more filled with carbon dioxide and nitrogen

earth is filled more with oxygen and nitrogen

mars is filled more with carbon dioxide and carbon monoxide

so ur answer is C

it cant be B as scientists and NASA are still in the look out for life, D has nothing to do with chemicals and atmosphere, and its not A cuz they all dont have the same similiar chemical.

~batmans wife dun dun dun....

6 0

3 years ago

Now, examine the structures of benzhydrol and fluorene. Both compounds contain the same number of carbons but have very differen

zubka84 [21]

Answer:

The OH group

Explanation:

Benzhydrol contains OH hydroxyl group in its molecule while fluorene does not. At first glance, one would think that OH, which contributes to hydrogen bonding would causes melting point of benzhydrol to be higher than fluorene. However, the structure of benzhydrol, which is 2 benzene rings connected to center hydroxyl carbon (PhCOHPh), allows for each benzene rings in benzhydrol to rotate until both rings are perpendicular to minimize repulsive force. This prevents the molecule from stacking on each other due to its non flat shape, and thus, lowering its melting point in contrast to flat fluorene molecule.

4 0

3 years ago