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
Yuki888 [10]
3 years ago
10

Multiple Questions, Brainliest and 98 points to whoever answers all questions correctly

Chemistry
2 answers:
suter [353]3 years ago
8 0

1

The average atomic  mass  of element  is  84.66

2

symbol    element    protons    neutrons   Electrons   mass No    Atomic No

Cs-133    cesium         55              78            55               133                55

Na-23      sodium         11                12            11                  23                  11

Ne 22       Neon           10              12            1 0                  22                  10        

Au -197     Gold            79             118            79                197                  79

3

The moles of tungsten   that are  in  93.50  grams are  0.509  moles

4

CO2  molecules at STP  are  1.547 x10^23  molecules

 Step  1:  find the  moles of CO2

At  STP    1 mole of a gas= 22.4 l

                                    ?  =5.75 L

all ik

otez555 [7]3 years ago
3 0

<u><em>Question 1</em></u>

The average atomic  mass  of element  is  84.66

<u>calculation</u>

Average  atomic mass is  of an element is the sum of masses of its isotope each  multiplied by its  natural  abundance.

that  is.

[(50.50 x  83.75) /100]   + [( 30.25 x 84.45)/100] + [(,9.25 x 87.40)/100]

=  42.29  +25.55 +16.82=  84.66



<u><em>Question 2</em></u>

fill the table

symbol    element    protons    neutrons   Electrons   mass No    Atomic No

Cs-133    cesium         55              78            55               133                55

Na-23      sodium         11                12            11                  23                  11

Ne 22       Neon           10              12            1 0                  22                  10        

Au -197     Gold            79             118            79                197                  79




<u><em>Question 3</em></u>

The moles of tungsten   that are  in  93.50  grams are 0.509  moles


moles=  mass/molar mass

 molar mass  of  tungsten  = 183.84 g/mol

moles  is therefore=  93.50  g/ 183.84  g/mol=  0.509  moles




<em><u>question  4</u></em>

CO2  molecules at STP  are 1.547 x10^23  molecules

 Step  1:  find the  moles of CO2

At  STP    1 mole of a gas= 22.4 l

                                    ?  =5.75 L

by cross multiplication

=  (5.75 L x 1 mole)/ 22.4 L= 0.257 moles

Step 2:  use the Avogadro's constant  to calculate the number of molecule

that is  1  moles = 6.02 x10^23 molecules

         0.257 moles= ? molecules

by  cross  multiplication

=(0.257 moles x 6.02  x 10^23) / 1 mole  = 1.547 x10^23  molecules



<u><em>question 5</em></u>

The number of calcium  atoms  is 3.82 x10^24  atoms

Step 1:  find the moles  of   calcium

= 253.50 g /40 g/mol= 6.34  moles


Step 2:  use the Avogadro's  law  to calculate the number of atoms.

that is   1 mole= 6.02 x 10^23 atoms

             6.34  moles=  ?  atoms

=6.34 x 6.02 x10^23  = 3.82  x10^24 atoms




<u><em>Question   6</em></u>

mass  in grams  of  NiBr2   is   126.97  grams

Step  1:  by use of  Avogadro's  law  constant  calculate  the  number  of moles


that  is  1 mole = 6.02 x 10^23

                 ?   =   3.50 x  10^23

by  cross  multiplication

= (1  mole  x 3.50  x10^23) /  6.02  x10^23 =0.581 moles

step 2:  calculate the  mass

mass =moles  x  molar mass

=  0.581 moles  x218.53 g/mol = 126.97 grams



 <u><em>Bonus question</em></u>

The molecules of water=  1.00  x10^26 molecules


  calculation

convert liters into  ml

= 3 x 1000  =  3000 ml

find the mass of  water

=  density  x volume

=3000  x0.998  2994  grams

find  the moles of water=mass/molar  mass

= 2994  g/  18  g/mol= 166.33 moles

Use  Avogadro's constant  to  calculate the molecules  of water

that is  1 mole=  6.02 x10^23  molecules

         166.33 moles= ? molecules

= (166.33 moles x6.02 x10^23 molecules) / 1 mole  =  1.00  x10^26  molecules

You might be interested in
PLEASEEEEE PLEASEEEEE ANSWER THIS QUESTION ILL GIVE BRAINLIEST AND 15 POINTSSSSS PLEASEEEEEEEEEEE!!!!!!!!!!
lozanna [386]
Hi what’s the question.... um
6 0
3 years ago
Read 2 more answers
Do metals form are anions or cations?
goldfiish [28.3K]

Answer: Metals form cations.

The alkali metals (the IA elements) lose a single electron to form a cation with a 1+ charge.

The alkaline earth metals (IIA elements) lose two electrons to form a 2+ cation.

Aluminum, a member of the IIIA family, loses three electrons to form a 3+ cation.

Therefore, metals in the s and p block of the periodic table have 1, 2 or 3 electrons in their outermost orbit (or valence shell). Now to gain a stable octet metals lose either 1, 2 or 3 electrons from the valence shell thus forming cation with +1, +2 or +3 charge.

5 0
3 years ago
Draw the resonance structures for the conjugate base of Phenol (C6H6O). In one sentence, explain why phenol (C6H6O) has a pKa of
notsponge [240]

Answer:

The four resonance structures of the phenoxide ion are shown in the image attached

The conjugate base of cyclohexanol has only one resonance contributor, while

the conjugate base of phenol has four resonance contributors.

Explanation:

In organic chemistry, it is known that structures are more stable if they possess more resonance contributors. The greater the number of contributing canonical structures, the more stable the organic specie. Since the phenoxide ion has four contributing canonical structures, it is quite much more stable than cyclohexanol having only one contributing structure to its conjugate base. Hence the PKa(acid dissociation constant) of phenol is lesser than that of cyclohexanol. The conjugate base of phenol is stabilized by resonance.

6 0
3 years ago
No spam or links! Thanks!
Monica [59]

Answer:

364 K or 91°C

Explanation:

Applying,

V₁/T₁ = V₂/T₂................ Equation 1

Where V₁ = Initial Volume, V₂ = Final volume, T₁ = initial Temperature, T₂ = final Temperature.

make T₂ the subject of the equation,

T₂ = V₂T₁/V₁................. Equation 2

From the question,

Given: V₁ = 375 mL, V₂ = 500 mL, T₁ = 0.0°C = (273+0) K = 273 K

Substitute these values into equation 2

T₂ = (500×273)/375

T₂ = 364 K

T₂ = (364-273) °C = 91 °C

5 0
3 years ago
The mass of an object is 216 g and the volume is 24 ml. What is the density
Stells [14]

Answer:

<h2>9 g/mL</h2>

Explanation:

The density of a substance can be found by using the formula

density =  \frac{mass}{volume} \\

From the question we have

density =  \frac{216}{24}  \\

We have the final answer as

<h3>9 g/mL</h3>

Hope this helps you

6 0
2 years ago
Other questions:
  • Explain why substances with a lower boiling point are removed near the top of a petroleum fractional distillation tower.
    15·1 answer
  • Temperature is used to measure the movement of particles such as atoms and molecules. as temperature increases, what is true of
    6·1 answer
  • A car moves at a speed of 50 kilometers/hour. Its kinetic energy is 400 joules. If the same car moves at a speed of 100 kilomete
    11·2 answers
  • Hydrogen cyanide is poisonous liquid that has a faint, almond-like smell. One molecule of hydrogen cyanide (HCN) is made up of o
    10·2 answers
  • How many hydrogen grams can be obtained if
    12·1 answer
  • A helium balloon is filled on the ground where the atmospheric pressure is 768 torr. The volume of the balloon is 8.00 m3. When
    5·1 answer
  • Which two of the following groups are very reactive?
    7·1 answer
  • 24. The only thing that Carbon, nitrogen and oxygen want is
    12·1 answer
  • SOMEONE PLEASE HELP
    8·1 answer
  • How do scientists use radioactive decay to date fossils and artifacts
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!