This chart show the amount of radioactivity measured from three unknown isotopes.


Which statement describes each of the isotopes?

Isotope A was measured at day 24, Isotope B was measured at day 6, and Isotope C was measured at day 10.
Isotope A was measured at day 18, Isotope B was measured at day 4, and Isotope C was measured at day 5.
Isotope A was measured at day 24, Isotope B was measured at day 8, and Isotope C was measured at day 20.
Isotope A was measured at day 30, Isotope B was measured at day 6, and Isotope C was measured at day 10.

Answer:

A

Explanation:

Answer:

B. 9

Explanation:

The formula of the compound is given as:

            9NaCl

Coefficient is the number before the compound. The compound here is made up of sodium and chlorine.

Therefore, we have 9 as the coefficient and it is 9 moles of NaCl.

Note, NaCl is an ionic compound.

Answer:

The dolphins average speed is 3.51 [tex]\frac{meters}{seconds}[/tex]

Explanation:

First of all, the following rules of three should be applied:

[tex]distance=\frac{20 miles*1609 meters}{1 mile}[/tex]

distance=32,180 meters

[tex]time=\frac{153 minutes*60 seconds}{1 minute}[/tex]

time= 9,180 seconds

Speed ​​is a physical quantity that expresses the relationship between the space traveled by an object and the time used for it. That is, speed implies the change of position of an object in space within a certain amount of time and is calculated as:

[tex]speed=\frac{distance}{time}[/tex]

So in this case the velocity is calculated as:

[tex]speed=\frac{32,180 meters}{9,180 seconds}[/tex]

Solving, you get:

Speed= 3.51 [tex]\frac{meters}{seconds}[/tex]

The dolphins average speed is 3.51 [tex]\frac{meters}{seconds}[/tex]

Answer:

C

Explanation:

Answer:

I think A, not sure

Explanation:

her weight depends on the force of gravity

Answer:

A is 2, B is 8, and C is 18

Explanation:

I did the Gizmos

The two, eight, and eighteen electrons can be filled in the first, second, and third energy levels respectively.

The electrons revolve in different orbits are known as energy levels or stationary states. These energy levels are numbered as n = 1, 2, 3…… These values are also known as the principal quantum numbers.

The first energy level is also known as 'K' shell or level. The second energy level is called 'L' shell, the third energy level is 'M' shell, and so on.

The electrons present in the K shell contain the least energy whereas the levels contain more energy that is far from the nucleus.

The first energy level (n = 1) can have maximum two electrons in it. The second energy level ( n= 2) can have maximum eight electrons and the third energy level can fill maximum eighteen electrons in it.

Learn more about energy levels, here:

https://brainly.com/question/17396431

#SPJ5

Answer:

13 moles of oxygen

Explanation:

A mole of a substance is the unit of measuring the number of particles within a chemical substance.

The given compound is:

      Ca₅ (PO₄)₃OH

This is a mole of   Ca₅ (PO₄)₃OH

  In this compound we have:

  5 moles of Ca

  3 mole of P

   13 mole of O

   1 mole of H

So,

  In 1 mole of  Ca₅ (PO₄)₃OH, we have 13 moles of oxygen

Answer:

there are 12 hydrogen atoms in 2 molecules of C3H6

Explanation:

Answer:

The amount of CaCO₃ Jeeves needs to find is approximately 71.392 grams

Explanation:

The given parameters are;

The mass of the CaO required = 40 g

The chemical reaction for the production of CaO from CaCO₃ is given as follows;

CaCO₃(s) → CaO(s) + CO₂(g)

Therefore, 1 mole of CaCO₃ produces 1 mole of CaO and 1 mole of CO₂,

The molar mass of CaO = 56.0774 g/mol

Number of moles, n = Mass/(Molar mass)

The number of moles of CaO = 40 g/(56.0774 g/mol) ≈ 0.7133 moles of CaO

Therefore, given that 1 mole of CaO is produced from 1 mole of CaCO₃ 0.7133 moles of CaO will be produced from 0.7133 moles of CaCO₃

The molar mass of CaCO₃ = 100.0869 g/mol

Mass = The number of moles × The molar mass

∴ The mass of CaCO₃ Jeeves needs to find = 0.7133 moles × 100.0869 g/mol ≈ 71.392 g

The mass of CaCO₃ Jeeves needs to find ≈ 71.392 grams.

Answer:

Electrical and magnetic

You exert a gravitational force on the pupil and the pupil exerts an equal gravitational force on you. ... The size of the gravitational force depends on the mass of the objects involved. The greater the mass, the greater the gravitational force.

Explanation:

Answer:

I think the answer would be B. hope this helps!!

Explanation:

Answer:

c! Hope this helps!

Explanation:

BRAINLIEST PLZ ;)

Answer:

I think its the third one im not sure tho

Explanation:

Answer:

108.3kPa

Explanation:

Given parameters:

Initial temperature  = 76k

Initial pressure  = 78.4kPa

Final temperature  = 105k

Unknown:

Final or new pressure  = ?

Solution:

To solve this problem, we apply the combined gas law:

           [tex]\frac{P_{1} }{T_{1} }[/tex]     =    [tex]\frac{P_{2} }{T_{2} }[/tex]

T1 = 76k

P1  = 78.4kPa

T2  = 105k

     [tex]\frac{78.4}{76}[/tex]   = [tex]\frac{P_{2} }{105}[/tex]  

     P2 = 108.3atm

Answer:

The object has to move a distance when a force is applied to it

Explanation:

For work to be done on a body the force applied must move the body through a particular distance.

  Work done  = Force x distance  

If no distance is moved by the force, no work is done.

Also, the angle between the force and the distance must be 0 to do the maximum work on the body.

Answer:

2.No. because in an open system, gas will blow up & so, if it's measured, it won't have the equal amount of the reactant. But, if you arrange this reaction in a closed system, then it will be the same.

3.2SiO2+4Cl2= 2SiCl4+O2

Explanation:

Answer:

a, u cannot bend rocks

Explanation:

........yjmumtwjmyjy

Answer:

Radio wave

Explanation:

Radio waves are a type of electromagnetic wave radiation with wavelengths in the electromagnetic spectrum longer than infrared light

A seismic wave is an elastic wave generated by an impulse such as an earthquake or an explosion.

Sound and water waves are mechanical waves; meaning, they require a medium to travel through.

Answer:

A Infiltration

Explanation:

The downward movement of water through pore spaces and other spaces in soil due to gravity is called infiltration.

Infiltration is greatly due to the force of gravity forcing water through pore spaces downward.

Answer: This law states that, despite chemical reactions or physical transformations, mass is conserved — that is, it cannot be created or destroyed — within an isolated system. In other words, in a chemical reaction, the mass of the products will always be equal to the mass of the reactants.

An empirical shows the simplest ratio among atoms in a compound .

Osmosis is of two types:

Endosmosis– When a substance is placed in a hypotonic solution, the solvent molecules move inside the cell and the cell becomes turgid or undergoes deplasmolysis. This is known as endosmosis.

Exosmosis– When a substance is placed in a hypertonic solution, the solvent molecules move outside the cell and the cell becomes flaccid or undergoes plasmolysis. This is known as exosmosis.

There are some variations or types of osmosis on the basis of the direction of the movement of solvent molecules.

Answer:

When our tear film becomes unstable, symptoms of Dry Eye can occur. OUR TEAR FILM HAS THREE LAYERS. Our tear film is made up of three layers – an oil (lipid) layer, a water (aqueous) layer and a mucin layer. ... Its main purpose is to seal the tear film which helps reduce evaporation of our natural tears.

Answer:

If the reaction requires energy, it is often indicated above the arrow. A capital Greek letter delta (Δ) is written on top of the reaction arrow to show that energy in the form of heat is added to the reaction; hv is written if the energy is added in the form of light.

Answer:

it means that to get the product, the reactants were heated

Answer:

1/8

Explanation:

Use logic,

every one hour, half of a radioactive remains

for the first hour, half remains

for the second hour, half of half remains or quarter remains

for the third hour, 1/2 of 1/2 of 1/2 or 1/8 remains

or use this equation

[tex]n = r ({ \frac{1}{2} })^{ \frac{f}{t} } [/tex]

where

n = amount after f time

r = amount of the original isotope

f = time

t = half-life

Answer:  The correct answer is:  " 0.54 g " .

__________________________________________

Explanation:

Note that "hydrogen gas" is:  

H₂ (g)  ;   that is:  a "diatomic element" (diatomic gas) ;

_________________________________________

The molecular weight of "H" is:  1.00794 g ;

   (From the Periodic Table of Elements).

So, the molecular weight of:  H₂ (g)  is:

    " 1.00794 g * 2  = 2.01588 g ; {use calculator) ;

_________________________________________

Note the conversion for a gas at STP:

______

  1 mol of a gas = 22.4 L gas;

___

i.e. " 1 mol / 22.4 L " ;

____

So:     " 5.7 L H₂ (g)  [tex]* \frac{1 mol H_{2} }{22.4 L} *\frac{2.01588 g}{mol} =? ;[/tex]

The "L" ("literes" cancel out to "1" ;  since "L/L = 1 ;

The "mol" (moles) cancel out to "1" ; since "mol/mol = 1 ;

____

and we are left with:

____

 [5.7 * 2.104588 g ] / 22.4  =  ?  g ;

______________________

→ [ 11.9961516  g ] / 22.4 =

          0.53554248214  g ;l

_____________________________

We round this value to:  " 0.54 g " ;

 → since "5.7 L " has 2 (two) significant figures;  

     22.4 is an exact number conversion;

     and "5.7 L" has fewer significant figures than:

    " 2.104588 " ; or:  " 1.00794 " .

  → as such: We round to "2 (two) significant figures."

______________________________

Hope this is helpful.  Wishing you the best in your academic endeavors!

_______________________________

Sample left = 6.25 g

The percentage = 6.25%

Given

t1/2 = half-life = 3.8 days

t = decay time = 15.2 days

No = initial sample = 100 g

Required

Nt = final sample left

The percentage

Solution

General formulas used in decay:  

[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]

Input the value :

[tex]\tt N_t=100.\dfrac{1}{2}^{15.2/3.8}\\\\N_t=100.\dfrac{1}{2}^4\\\\N_t=6.25~g[/tex]

The percentage : Nt/No

6.25 : 100 = 6.25%

Answer:

Sodium reacts more quickly, generating enough heat to melt itself and to occasionally ignite the hydrogen gas, producing a yellow-orange flame characteristic of sodium. The potassium reacts violently, immediately bursting into a flame which has the characteristic violet color of potassium.

Explanation:

Answer:

no

Explanation:

Answer:

I think C but it could be D

Explanation:

I would say go for C