Give the molar mass of Zn(OH)2

A bomb calorimeter has a heat capacity of 2.18 kJ/K. When a 0.176g sample of gas with a molar mass of 28.0 g/mol was burned in t

irina1246 [14]

Answer:

Heat of combustion =-7.35 *10² kJ

Explanation:

Step 1: Data given

Mass = 0.176 grams

Molar mass = 28.0 g/mol

Temperature increase 2.12 K

A bomb calorimeter has a heat capacity of 2.18 kJ/K

Step 2: Calculate heat of combustion

Energy released = mass *heat capacity* change in temperature

Q = c*∆T

Q = 2.18 kJ/K*2.12 K = 4.62 kJ released

Heat of combustion = (energy released)/(mole of substance)

Moles of gas = (0.176 g)/(28.0 g/mol) = 0.00629 moles

Heat of combustion = (energy released)/(mole of substance)

Heat of combustion = (4.62 kJ)/(0.00629 moles) = 7.35 *10² kJ

Heat of combustion =-7.35 *10² kJ (negative because heat is lost)

6 0

3 years ago

What is the chemical formula for the compound ammonium phosphate? Use the list of polyatomic ions and the periodic table to help

Talja [164]

Answer: The correct answer is Option C.

Explanation:

We are given some polyatomic ions with their oxidation states. Polyatomic ions are defined as the ions which are formed from more than 2 atoms.

We need to find out the chemical formula for ammonium phosphate.

For this, the polyatomic ions used are:

Ammonium ion - $NH_4^+$

Phosphate ion - $PO_4^{3-}$

By using criss-cross method, the oxidation state of the ions are exchanged and they form the subscripts of the other ions. This results in the formation of a neutral compound.

Thus, the chemical formula for this compound is $(NH_4)_3PO_4$

Hence, the correct answer is Option C.

4 0

4 years ago

Read 2 more answers

What other element had the same number of electrons as potassium??

sergiy2304 [10]

Answer:

Potassium is the only element with 19 electrons.

Explanation:

4 0

3 years ago

Indicate which solution in each pair has the lower pH. Your response should be a four letter "word". The first letter should be

JulijaS [17]

Answer:

bcfh

Explanation:

HClO₄ reacts with water thus:

HClO₄ + H₂O → H₃O⁺ + ClO₄⁻

That means HClO₄ produce H₃O⁺ that decreases pH. That means the higher concentration of HClO₄ decreases pH. Thus, lower pH will be:

b) 0.2 M HClO4

The reaction of NaClO₄ is:

NaClO₄ + H₂O → OH⁻ + HClO₄ + Na⁺

The higher concentration of NaClO₄ the higher production of OH⁻ that increase pH, that means the lower concentration of NaClO₄ the lower pH, thus, the answer is:

c) 0.1 M NaClO or

HF reacts with water thus;

HF ⇄ H⁺ + F⁻

The equilibrium constant is:

k = [H⁺] [F⁻] / [HF] = 3,5x10⁻⁴

For HNO₂ equilibrium is:

HNO₂ ⇄ H⁺ + NO₂⁻

k = [H⁺] [NO₂⁻] / [HNO₂] = 4,5x10⁻⁴

As k value is higher for HNO₂, the concentration of H⁺ will be higher in this system doing the HNO₂ with the lower pH.

f) 0.1 M HNO2

NaOH is a strong base that produce OH⁻ that increase pH, pure water is neutral, thus, the lowe pH is:

h) pure water

I hope it helps!

7 0

4 years ago

Other than through sexual reproduction, how can variations in genetic material occur in a population?

melomori [17]

Answer:

Through their adaptations from their habitat; environment

Explanation:

Charles Darwin explains evolution and their genetic material evolves during the process. For example, fruit birds have narrow bills whilst seed-eating birds have big bills. The foods they eat forced their DNA to adapt with the system in order to survive.

5 0

3 years ago