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
ziro4ka [17]
2 years ago
9

an atom has 79 protons, 78 electrons and a mass number of 118. how many neutrons does this atom have​

Chemistry
1 answer:
igomit [66]2 years ago
4 0

Answer:

39

Explanation:

Electrons weigh almost nothing, so their mass doesn't really matter for these types of problems. Just subtract 118-79 to find the remaining mass which is for the neutrons.

You might be interested in
The water cycle is the movement of water from Earth's surface to the atmosphere and back to Earth's surface. Why do many living
sladkih [1.3K]
The water cycle renews water supplies by moving water from the oceans, as freshwater, to land
7 0
3 years ago
Read 2 more answers
Bond energy needed to break or create bonds is measured in units called
MatroZZZ [7]

Answer:

C. kilojoules

Explanation:

The bond energy needed to break or create bonds is measured in units called kilojoules.

Bond energy is a form of enthalpy change of a reaction or physical change. The bond energy is the heat content of a covalent bond formed from its constituent elements in the gas phase.

The bond energy is the same in value as the bond dissociation energy and its unit is given in kilojoules.

4 0
3 years ago
Balance the equation for <br> __Ca+__Pb(NO3)2—__Pb+__Ca(NO3)2
svp [43]

Answer:

Ca + Pb(NO3)2 → Pb + Ca(NO3)2

Explanation:

This is an oxidation-reduction (redox) reaction:

PbII + 2 e- → Pb0

(reduction)

Ca0 - 2 e- → CaII

(oxidation)

Pb(NO3)2 is an oxidizing agent, Ca is a reducing agent.

5 0
2 years ago
Carbon-14 has a half-life of 5720 years and this is a first order reaction. If a piece of wood has converted 75% of the carbon-1
liraira [26]

Answer: 1145.8 years

Explanation:

Half-life of carbon-14 = 5720 years

First we have to calculate the rate constant, we use the formula :

k=\frac{0.693}{5720\text{years}}

k=1.21\times 10^{-4}\text{years}^{-1}

Now we have to calculate the age of the sample:

Expression for rate law for first order kinetics is given by:

t=\frac{2.303}{k}\log\frac{a}{a-x}

where,

k = rate constant  = 1.21\times 10^{-4}\text{years}^{-1}

t = age of sample  = ?

a = let initial amount of the reactant  = 100 g

x = amount decayed = 75 g

a - x = amount left after decay process  = 100 - 75 = 25g

Now put all the given values in above equation, we get

t==\frac{2.303}{1.21\times 10^{-4}}\log\frac{100}{25}

t=1145.8years

8 0
3 years ago
Read 2 more answers
PLEASE HELP: You have been given 0.507 moles of cesium fluoride (CsF), determine the mass in grams of cesium fluoride that you h
Degger [83]

Answer:

C because 77.0 CsF

Explanation:

That is the correct answer because I have that homework and i got it right

5 0
2 years ago
Other questions:
  • What does it mean to discuss the concentration of a solution
    5·1 answer
  • Find the mass of 250.0mL of benezene. The density of benezene is 0.8765 g/mL
    15·2 answers
  • New Pressure of gas when temp is 235 k
    9·1 answer
  • Waves that can travel through empty space are called
    9·1 answer
  • Is air a mixture or pure substance ​
    12·1 answer
  • What is E=mc2? please be specific.
    11·1 answer
  • Write a balanced half-reaction for the reduction of permanganate ion (Mno) to manganese ion Mn?) in acidic aqueous solution. Be
    12·1 answer
  • How many kPa are in 924.8 torr?
    9·1 answer
  • What does the entropy of a reaction describe?
    15·2 answers
  • Why is platinum metal preferred to other metals for the flame test​
    8·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!