All categories

2 years ago

I need some help on this.

Chemistry

2 answers:

Orlov [11]2 years ago

5 0

Answer:

I think the right answer is c/ number of atomic orbitals

laila [671]2 years ago

5 0

It’s metallic character hope this help

You might be interested in

A sample of gas at a pressure of 121.59 kPa, a volume of 31 L, and a temperature of 360 K contains how many moles of gas? A. 0.7

natali 33 [55]

Answer:

C. 1.3 mol

Explanation:

PV = nRT

where P is absolute pressure,

V is volume,

n is number of moles,

R is universal gas constant,

and T is absolute temperature.

Given:

P = 121.59 kPa

V = 31 L

T = 360 K

R = 8.3145 L kPa / mol / K

Find: n

n = PV / (RT)

n = (121.59 kPa × 31 L) / (8.3145 L kPa / mol / K × 360 K)

n = (3769.29 L kPa) / (2993.22 L kPa / mol)

n = 1.26 mol

Round to two significant figures, there are 1.3 moles of gas.

4 0

3 years ago

A Cyclist rode at an average speed of 10mph for 15 miles. how long was the ride

Setler79 [48]

Hey there Abigaildonaimor,

A cyclist rode at an average speed of 10mph for 15 miles. How long was the ride?

Answer:

Time = Distance / Rate
= 15 miles / 10mph
= 1.5 hours

Hope this helps :D

~Natasha♥

6 0

3 years ago

Read 2 more answers

In many of the steps in the lab, a mixture was centrifuged and then decanted. In general terms, what is accomplished by these st

nirvana33 [79]

Answer:

to separate the compounds by gravity

Explanation:

Centrifuging is the process of separating compound in a liquid mixture by means of gravity and settling. This makes use of the density principle. In the process, the sample is added to the centrifuge. This is then rotated at a certain speed, say 50 rpm. The circular motion creates a force of gravity that pulls the compounds downwards. This then separate the compounds. The heaviest and most dense go down first, then the lighter particles on the top.

3 0

3 years ago

A solution containing 0.102 g of an unknown compound dissolved in 100. mL of water has an osmotic pressure of 28.1 mmHg at 20.°C

IrinaVladis [17]

Answer:

MM = 680g / mol

Explanation:

Hello! To calculate the molar mass of the compound (g / mol), I first have to calculate the molarity.

Molarity can be calculated from the osmotic pressure equation.

op = M * R * T

op = osmotic pressure = 28.1mmHg * (1 atm / 760mmHg) = 0.037atm

M = molarity

R = gas constant

T = temperature (K) = 20 ° C + 273.15 = 293.15K

M (mol / L) = op / R * T

M = 0.037atm / ((0.082 (atm * L) / (K * mol)) * 293.15K) = 0.0015mol / L

As I have the volume = 100ml * (1L / 1000ml) = 0.1L

I can calculate the amount of moles

n = M * V = 0.0015 * 0.1 = 0.00015mol

n = m / MM

m = mass

MM = molar mass

MM = m / n = 0.102g / 0.00015mol

MM = 680g / mol

4 0

3 years ago

Read 2 more answers

Why does magnesium oxide have a high melting point?

Mandarinka [93]

Magnesium oxide is an ionic compound ( because it consists of a metal and a non-metal)

In ionic compounds, electrons from the outer shell exchange between the atoms so that they each get a full outer shell. Once these electrons are exchange, the atoms will become ions. One ion will have a positive charge, and the other ion will have a negative charge. The positive and negative ions then bond strongly together in a lattice structure, due to the electrostatic forces of attraction.

These electrostatic forces of attraction are very strong and require a lot of energy to break, as such the compound will have a high melting point.

__________________________________________

Now lets look at the ionic bonding between magnesium and oxygen:

In the outer shell of Magnesium, there are 2 electrons.

In the outer shell Oxygen, there are 6 electrons.

Magnesium gives it's two electrons to Oxygen, so that the Oxygen now has a full outer shell of 8 electrons. However, since Oxygen gained two electrons, it will form a negatively charged ion with a charge of -2.

Since Magnesium lost the two electrons, it's second shell (which has 8 eletrons) now becomes the outer shell. So Magnesium also now has a full outer shell. But since it has lost two electrons, it becomes a positively charged ion with a charge of + 2.

The positive Magnesium ion and negative Oxygen ion and now strongly attracted to each other, and form a strong ionic compound (magnesium oxide) with a lattice structure.

The electrostatic forces of attraction between the positive Magnesium and negative Oxygen are so strong that a lot of heat and energy are needed to break them.

Therefore magnesium oxide has a high melting point.

5 0

2 years ago