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
Lana71 [14]
3 years ago
13

7. Which of the following pairs of atoms are isotopes? a) C14 & N14 b) U235 & U238 c) C12 & C12 d) C12 & N14 e)

None of the choices are correct
Chemistry
1 answer:
Ede4ka [16]3 years ago
3 0

Answer:

b) U235 & U238

Explanation:

Isotopes are the variants of a element which differ in the number of neutrons , and in the nucleon number consequently . All isotopes of the element have same number of the protons but different numbers of the neutrons.

(a) Isotopes are the properties of an element. Hence, not isotopes.

(b) Uranium is the element which exists in mass number 235 and 238 and they are the isotopes of the uranium element. Hence, they are isotopes.

(c) They represent same specie. Hence, not isotopes.

(d) Isotopes are the properties of an element. Hence, not isotopes.

You might be interested in
8. Bring the balloon in contact with the wall. What happens to the charges in the wall?
Ne4ueva [31]

When the charged balloon is brought near the wall, it repels some of the negatively charged electrons in that part of the wall. Therefore, that part of the wall is left repelled.

<u>Explanation</u>:  

  • Balloons don't stick to walls. However, if you rub the balloon on an appropriate piece of material such as clothing or a wall, electrons are pulled from the other material to the balloon.
  • The balloon now as more electrons than normal and therefore has an overall negative charge. Two balloons like this will repel each other.
  • The other material now has an overall positive charge. Because opposite charges attract, the balloon will now appear to stick to the other material. If you didn't rub the balloon first, it's charge would be neutral and it wouldn't stick to the wall.
7 0
3 years ago
How long does it take for a 12.62g sample of ammonia to heat from 209K to 367K if heated at a constant rate of 6.0kj/min? The me
Georgia [21]
First, consider the steps to heat the sample from 209 K to 367K.

1) Heating in liquid state from 209 K to 239.82 K

2) Vaporaizing at 239.82 K

3) Heating in gaseous state from 239.82 K to 367 K.


Second, calculate the amount of heat required for each step.

1) Liquid heating

Ammonia = NH3 => molar mass = 14.0 g/mol + 3*1g/mol = 17g/mol

=> number of moles = 12.62 g / 17 g/mol = 0.742 mol

Heat1 = #moles * heat capacity * ΔT

Heat1 = 0.742 mol * 80.8 J/mol*K * (239.82K - 209K) = 1,847.77 J

2) Vaporization

Heat2 = # moles * H vap

Heat2 = 0.742 mol * 23.33 kJ/mol = 17.31 kJ = 17310 J

3) Vapor heating

Heat3 = #moles * heat capacity * ΔT

Heat3 = 0.742 mol * 35.06 J / (mol*K) * (367K - 239.82K) = 3,308.53 J

Third, add up the heats for every steps:

Total heat = 1,847.77 J + 17,310 J + 3,308.53 J = 22,466.3 J

Fourth, divide the total heat by the heat rate:

Time = 22,466.3 J / (6000.0 J/min) = 3.7 min

Answer: 3.7 min


3 0
3 years ago
3. How many moles of NaCl are present in 6000. La 1.5 M NaCl solution?
Leno4ka [110]

Answer:

Option A (9.0) is the correct alternative.

Explanation:

The given values are:

Molarity,

= 1.5 M

Volume,

= 6000 mL

or,

= 6 L

As we know,

⇒ Molarity=\frac{Moles}{Volume}

or,

⇒ The \ moles \ of \ NaCl=Molarity\times Volume

By putting the values, we get

                                     =1.5\times 6

                                     =9 \ mol

7 0
3 years ago
Determine the percentage composition of Ptl2
Hitman42 [59]

Answer:

Percent Composition

1. Find the molar mass of all the elements in the compound in grams per mole.

2. Find the molecular mass of the entire compound.

3. Divide the component's molar mass by the entire molecular mass.

4. You will now have a number between 0 and 1. Multiply it by 100% to get percent composition.

7 0
2 years ago
Using the periodic table, determine which material is most likely to be a good conductor. A. sodium B. bromine C. carbon D. oxyg
grandymaker [24]
A. Because sodium is a metal and metals are good conductors
7 0
3 years ago
Other questions:
  • Why are familiar objects such as pens and paper clips not commonly counted in moles?
    14·2 answers
  • Mass is an intensive physical property because it is dependent on the size of the sample.
    5·2 answers
  • Everyday examples of combined gas laws
    7·1 answer
  • Make a model for the the ionic bonding of Al and Cl.
    13·1 answer
  • Base your answer on the information below. The hydrocarbon 2-methylpropane reacts with iodine as represented by the balanced equ
    5·1 answer
  • Select all of the answers that apply.
    8·2 answers
  • Which of the following is a non polar molecule ?
    12·1 answer
  • Help me with this question please
    10·1 answer
  • Edmentum
    6·1 answer
  • Find the appropriate number of significant figures
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!