In order to amend the Articles of Confederation, how many votes were needed? A) 7 B) 9 C) 10 D) 13

how are subscripts determine the formula of ionic and covalent compounds ?

RideAnS [48]

Answer:

To determine the correct subscripts in a chemical formula, you have to solve how many atoms you need to balance the charge.

For example if I had the compound Calcium Fluoride I would look at the periodic table and see that Calcium's ionic formula is

Ca2+

. How do I know this? Well all elements want to have 8 valance electrons so they can be stable(happy). Seeing that Calcium has 2 valance electrons it is going to give away 2 electrons because that is easier than gaining 6 to be happy. Since Calcium has given away 2 electrons it has two more protons than electrons. We know that Protons have a Positive charge, Electrons have Negative charge, and the number of electrons is equal to the atomic number of an element in its pure non-ionic state. (Meaning it doesn't have a positive or negative charge; it is balanced.)

So if calcium gave away two electrons, it will have two more protons than an electron giving it a (2+) charge. The same process can be applied to Fluoride. Since fluoride is one to the left of the noble gases(group 18 or 8A) on the periodic table we know that it has 7 valance electrons because it is in group 7A or 17.

Knowing that we have 7 electrons the fluoride atom will gain an extra electron. Since the fluoride atom gained an extra electron it will have one more negative charge than a positive making it a ^(−)ion.

So you know that Calcium has a 2+ charge and that fluoride has a 1- charge, you then need these ions to balance out. So you need two fluorine atoms with a 1- ions to balance out the 2+ ion of calcium. Your final answer would be

CaF2

because you need two fluorine atoms to balance out the 2+ charge of the calcium.

Final Tip: Determine the charges then inverse the charges, remove the positive and negative superscipts, and write the charge numbers as a sub script. Ie. Calcium Fluoride

Ca2+ and F−

inversing and removing the charge signs would give you

4 0

3 years ago

What is the outcome of the experoment?

Vikki [24]

The outcome of a experiment is the result

3 0

3 years ago

⦁answer Calculate the density in g/L of 478 mL of krypton at 47° C and 671 mm Hg. ⦁ Determine the molar mass of a gas that has a

STALIN [3.7K]

Answer:

The correct answers are:

- Krypton: density= 2.8 g/L

- Molar Mass= 63.99 g/mol

- Mass of O₂= 15.29 g

Explanation:

The general equation of an ideal gas is the folllowing:

P x V = n x R x T

Where: P= pressure (in atm), V= volume; n= number of moles, R= gas constant (0,082 L.atm/K.mol) and T= temperature (in K).

For krypton:

P= 671 mmHg = 0,882 atm

V= 478 ml x 1000 ml/1 L= 0,478 L

T= 47ºC= 320 K

MM= 83.8 g/mol (from Periodic Table, Kr is an inert gas so it is a monoatomic gas)

P x V = n x R x T

Since the number of moles of a compound can be calculated by dividing the mass of compound (m) into its molar mass (MM):

n= m/MM

We can replace the expression in the first equation to obtain:

$P x V= \frac{m}{MM} x R x T$

m/V= $\frac{P x MM}{R x T}$

Density (d) is equal to the mass per volume (m/V), so we can directly calculate the density:

d= m/V= \frac{P x MM}{R x T}=

= (0.882 atm x 83.8 g/mol)/(0.082 L.atm/K.mol x 320 K)

= 2.81 g/L

For the gas:

d= 2.18 g/L

T= 66ºC= 339 K

P= 720 mmHg= 0.947 atm

d= \frac{P x MM}{R x T}

⇒MM = $\frac{dx R x T}{P}$

= (2.18 g/L x 0.082 L.atm/K.mol x 339 K)/(0.947 atm)

= 63.99 g/mol ≅ 64 g/mol

For the O₂:

V= 5.60 L

P= 1.75 atm

T= 250 K

MM(O₂) = 2 x Atomic Mass O= 2 x 16 g/mol= 32 g/mol

We can use the second equation:

P x V= \frac{m}{MM} x R x T

⇒ m = $\frac{P x V x MM}{R x T}$ = (1.75 atm x 5.6 L x 32 g/mol)/(0.082 L.atm/K.mol x 250 K)

= 15.29 g≅ 16 g

4 0

3 years ago

Read 2 more answers

Which of the following will dissolve most quickly? A. two sugar cubes. . B. a tablespoon of coarse sugar. . C. a tablespoon of t

Dimas [21]

The one that will dissolve most quickly is : D. a tablespoon of ultrafine sugar

Unlike any other type of sugar, ultrafine sugar tend to have smaller crystal size. Which means that this substance will dissolve easier if it put into liquid such as tea or water

hope this helps

3 0

3 years ago

Read 2 more answers

blants, water moves in a continuous column in direction. Both One direction, down only One direction, up only Any way it wants t

Fittoniya [83]

Answer:

i like one direction

Explanation:

5 0

2 years ago