1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
soldier1979 [14.2K]
2 years ago
5

How much heat does it take to melt 2.5 kg of lead when it is at its melting point (m.p. = 327.5°C; Hf = 2.04 × 104 J/kg)?

Chemistry
2 answers:
irinina [24]2 years ago
6 0
1. the amount of heat that it would take would be :
5.1 x 10^4 J

2. I think the substance would be : Iron

3. the amount of heat required would be :
1.13 x 10^4 kJ

Hope this helps
Vedmedyk [2.9K]2 years ago
5 0

(1) Enthalpy of fusion is given as 2.04*10^4\frac{J}{kg} . It means 2.04*10^4 J of heat is required to melt 1 kg of lead. We are asked to calculate the heat required to melt 2.5 kg of lead.

q=m\Delta H_f

where m is the mass and \Delta H_f is the enthalpy of fusion.

let's plug in the values in the formula:

q=2.5kg*2.04*10^4\frac{J}{kg}

q=5.1*10^4J

(2) From given heat energy and mass we can calculate the enthalpy of fusion and then match it with the values given in the table and see which metal is it.

\Delta H_f=\frac{q}{m}

\Delta H_f=\frac{2.52*10^5J}{4.00kg}

\Delta H_f=6.3*10^4\frac{J}{kg}

Looking at the standard table, the substance is Gold as it has same enthalpy of fusion value that we have calculated.

(3) Heat of vaporization is used when the liquid changes into vapor. Heat of condensation is used when the vapor changes into liquid and the heat of solidification is used when the liquid freezes.

In question it asks, what would be used to calculate the heat released when a liquid freezes. So, the right option is "Heat of solidification."

(4) This is exactly Similar to the first one, the only difference is, here we will use the enthalpy of vaporization.

q=m\Delta H_v

q=0.200kg*2.26*10^3\frac{kJ}{kg}

q=4.52*10^2kJ

First option is correct.

You might be interested in
Predict the splitting pattern for each of the labeled hydrogens in the following molecules. Assume that all coupling constants a
Ghella [55]

Complete Question

The complete question is shown on the first uploaded image

Answer:

a) Splitting pattern for Ha= 2+1 , Triplet

For Proton Hb and Hc both are equivalent to each other. non equivalent protons n= 3

Splitting pattern for Hb and Hc= 3+1 , Quartet

For Proton Hd, number of non equivalent protons n= 0

Splitting pattern for Hd= 0+1 , Singlet

b) Splitting pattern for Ha= 2+1 , Triplet

For Proton Hb and Hc both are equivalent to each other. non equivalent protons n= 3

Splitting pattern for Hb and Hc= 3+1 , Quartet

For Proton Hd, number of non equivalent protons n= 0

Splitting pattern for Hd= 0+1 , Singlet

c) The IUPAC name is Butan-2-ol

Explanation:

Considering the first question the rule used for prediction of splitting pattern is n+1 (Pascal's Triangle rule), where n is number of H atom on the adjacent carbon which are non equivalent.

According to that for molecule 1 as shown on the second uploaded image

For Proton Ha, number of non equivalent protons n= 2

Splitting pattern for Ha= 2+1 , Triplet

For Proton Hb and Hc both are equivalent to each other. non equivalent protons n= 3

Splitting pattern for Hb and Hc= 3+1 , Quartet

For Proton Hd, number of non equivalent protons n= 0

Splitting pattern for Hd= 0+1 , Singlet

Considering the second question for Molecule 2 as shown on the third uploaded image  

For Proton Ha, number of non equivalent protons n= 1

Splitting pattern for Ha= 1+1=2 , Doublet

For Proton Hb, number of non equivalent protons n= 3

Splitting pattern for Hb= 3+1=4 , Quartet

For Proton Hc, number of non equivalent protons n= 3

Splitting pattern for Hc= 3+1=4 , Quartet

For Proton Hd, number of non equivalent protons n= 1

Splitting pattern for Ha= 1+1=2 , Doublet

Considering the third question

The name of the given molecule  is gotten according to longest carbon chain  = 4 (Prefix 'Butan')

Functional group = -OH (Suffix 'ol') at C-2

The IUPAC name is Butan-2-ol

3 0
3 years ago
E)¿Cuántos átomos de oxigeno hay en la molécula de glucosa, al reaccionar 12moleculas de agua?
elena55 [62]

Answer:

12 átomos de oxígeno hay presentes

Explanation:

Basados en la reacción:

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

<em>6 moles de agua producen 1 mol de glucosa</em>

<em />

Si reaccionan 12 moleculas de agua, se producirán:

12 moleculas H₂O * (1 mol C₆H₁₂O₆ / 6 mol H₂O) =

2 moléculas de glucosa se producen.

Como cada molécula de glucosa tiene 6 átomos de oxígeno:

2 moléculas C₆H₁₂O₆ * (6 átomos Oxígeno / 1 molécula C₆H₁₂O₆) =

<h3>12 átomos de oxígeno hay presentes</h3>

6 0
3 years ago
In general, as you move from right to left across a period, the number of valence electrons
goblinko [34]
As you move from left to right across a period,the number of valence electrons<span>-increases. </span>
4 0
3 years ago
Read 2 more answers
PLZ HELP!!! ILL MARK BRAINLIEST!!! You read an article written by an amateur ghost hunter. It includes the following paragraph.
djverab [1.8K]

No, it is not a scientific claim. If a ghost hunter catches a voice on video like ghost hunters do you can either believe it or not. Ghosts are more of a  i believe it you dont have to type of thing becasue they have not been scientifically proven to exist.

4 0
3 years ago
Read 2 more answers
An element that can have different physical properties or chemical arrangement is called a (n)
shusha [124]
<h3>Answer:</h3>

D. Allotrope

<h3>Explanation:</h3>

What is allotropy?

  • Allotropy refers to the existence of an element in more than one physical forms.
  • Allotropes are therefore different forms of an element with different physical properties or chemical arrangements.

What are some examples of allotropes?

  • Examples of elements that exhibit allotropy include, sulfur and carbon.
  • Allotropes of carbon are diamond and graphite.
  • Allotropes of sulfur are monoclinic sulfur and rhombic sulfur.
3 0
3 years ago
Other questions:
  • The energy released by a nuclear reaction results primarily from the
    14·2 answers
  • I NEED THE ANSWER TO NUMBER 3 pleaseee
    13·1 answer
  • Consider this reaction mechanism: Step 1: Mo(CO)6→ Mo(CO)5 + CO Step 2: Mo(CO)5 + P(CH3)3→ Mo(CO)5P(CH3)3 Which of these is an i
    7·1 answer
  • Why do solids react faster in powder form than in lump form
    7·1 answer
  • How Many protons is there
    12·1 answer
  • Why do atoms share electrons in covalent bonds??
    8·2 answers
  • How many atoms are in .800 g of Ca
    8·2 answers
  • Assume that the complete combustion of one mole of glucose, a monosaccharide, to carbon dioxide and water liberates 2870 kJ2870
    12·1 answer
  • What do electrons Do in ionic bond? Do they transfer from metals to no metals or nonmetal to metals?
    6·1 answer
  • Does water burn? for my sister that says water does burn
    9·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!