Which of the following elements is most metallic?

What is the pattern in the periodic table for valence electrons and orbital shells of an element?

IRISSAK [1]

Answer:

Valence electrons increase as you go across the table (by periods)

Orbital Shells increase as you go down the table (rows)

7 0

3 years ago

Read 2 more answers

Shoals are raised landforms made of sand and gravel that are commonly found in Florida. They are often called sandbars and are l

Licemer1 [7]

Formation. Wave shoaling is the process when surface waves move towards shallow water, such as a beach, they slow down, their wave height increases and the distance between waves decreases. This behavior is called shoaling, and the waves are said to shoal.

Heavy rain fall causes shoals to form and change shape creating depressions and bars in the sand

6 0

3 years ago

Read 2 more answers

A certain liquid has a normal boiling point of and a boiling point elevation constant . A solution is prepared by dissolving som

PSYCHO15rus [73]

This question is incomplete, the complete question is;

A certain liquid X has a normal boiling point of 150.4 °C and a molar boiling point elevation constant kb is 0.60 °Ckgmol⁻¹.

A solution is prepared by dissolving some urea (NH22CO) in 750 g of X. This solution boils at 150.9 °C . Calculate the mass of urea that was dissolved. Round your answer to 3 significant digits.

Answer:

the mass of urea that was dissolved is 37.5 g

Explanation:

Given the data in the question;

normal boiling point of X; Tb⁰ = 150.4 °C

boiling point of solution Tb = 150.9 °C

Change in boiling point Δt = Tb - Tb⁰ = 150.9 °C - 150.4 °C = 0.5 °C

Kb = 0.6 °C.kg.mol⁻¹

V = 750 g

Now, we know that

Δt = Kb × molality

so

0.5 = 0.6 × molality

molality = 0.5 / 0.6

molality = 0.833

we know that molar mass of urea is 60 g/mol

so

molality = mass × 1000 / molar mass × volume( g )

we substitute

0.833 = ( mass × 1000 ) / ( 60 × 750 )

0.833 = ( mass × 1000 ) / 45000

0.833 × 45000 = mass × 1000

mass = ( 0.833 × 45000 ) / 1000

mass = 37485 / 1000

mass = 37.485 ≈ 37.5 g { 3 significance figure }

Therefore, the mass of urea that was dissolved is 37.5 g

8 0

3 years ago

The method used by Joseph Priestley to obtain oxygen made use of the thermal decomposition of mercuric oxide given below. What v

sukhopar [10]

Answer:

The volume of the oxygen gas is 0.246 L

Explanation:

Step 1: Data given

Temperature = 39 °C = 312 K

Temperature = 725 torr = 725 / 760 atm = 0.953947 atm

Mass of mercuric oxide = 3.97 grams

Molar mass of mercuric oxide = 216.59 g/mol

Step 2: The balanced equation

2HgO → 2Hg + O2

Step 3: Calculate moles mercuric oxide

Moles = mass / molar mass

Moles HgO = 3.97 grams / 216.59 g/mol

Moles HgO = 0.0183 moles

Step 3: Calculate moles oxyen

For 2 moles HgO we'll have 2 moles Hg and 1 mol O2

For 0.0183 moles HgO we'll have 0.0183/2 = 0.00915 moles O2

Step 4: Calculate volume O2

p*V = n*R*T

⇒with p = the pressure of the gas = 0.953947 atm

⇒with V = the volume of O2 gas = TO BE DETERMINED

⇒with n = the moles of O2 = 0.00915 moles

⇒with R = the gas constant = 0.08206 L*atm/mol*K

⇒with T = the temperature = 312 K

V = (n*R*T)/p

V = (0.00915 moles * 0.08206 L*atm/mol*K * 312 K ) / 0.953947 atm

V = 0.246 L

The volume of the oxygen gas is 0.246 L

3 0

3 years ago

Which of the following statements best describes a food web?

Anastaziya [24]

Answer:

Its either B or D. I personally would go with B

Explanation:

5 0

3 years ago