a radioactive element has a half-life of 30 days. calculate the mass of the element that remains after 20 days if 100g of the element decays. Also, calculate the decay constant.

Answers

Answer 1

Answer:

A=Ao(1/2)^t/h

A=(100)(1/2)^20/30

A=63g


Related Questions

A gas has a volume of 4.25 m3 at a temperature of 95.0°C and a pressure of 1.05 atm. What temperature will the gas have at a pressure of 1.58 atm and a volume of 2.46 m3

Answers

Answer:

[tex]\boxed {\boxed {\sf 82.7 \textdegree C}}[/tex]

Explanation:

We are asked to find the temperature of a gas given a change in pressure and volume. We will use the Combined Gas Law, which combines 3 gas laws: Boyle's, Charles's, and Gay-Lussac's.

[tex]\frac {P_1V_1}{T_1}=\frac{P_2V_2}{T_2}[/tex]

Initially, the gas has a pressure of 1.05 atmospheres, a volume of 4.25 cubic meters, and a temperature of 95.0 degrees Celsius.

[tex]\frac {1.05 \ atm * 4.25 \ m^3}{95.0 \textdegree C}= \frac{P_2V_2}{T_2}[/tex]

Then, the pressure increases to 1.58 atmospheres and the volume decreases to 2.46 cubic meters.

[tex]\frac {1.05 \ atm * 4.25 \ m^3}{95.0 \textdegree C}= \frac{1.58 \ atm *2.46 \ m^3}{T_2}[/tex]

We are solving for the new temperature, so we must isolate the variable T₂. Cross multiply. Multiply the first numerator by the second denominator, then multiply the first denominator by the second numerator.

[tex](1.05 \ atm * 4.25 \ m^3) * T_2 = (95.0 \textdegree C)*(1.58 \ atm * 2.46 \ m^3)[/tex]

Now the variable is being multiplied by (1.05 atm * 4.25 m³). The inverse operation of multiplication is division, so we divide both sides by this value.

[tex]\frac {(1.05 \ atm * 4.25 \ m^3) * T_2}{(1.05 \ atm * 4.25 \ m^3)} = \frac{(95.0 \textdegree C)*(1.58 \ atm * 2.46 \ m^3)}{(1.05 \ atm * 4.25 \ m^3)}[/tex]

[tex]T_2=\frac{(95.0 \textdegree C)*(1.58 \ atm * 2.46 \ m^3)}{(1.05 \ atm * 4.25 \ m^3)}[/tex]

The units of atmospheres and cubic meters cancel.

[tex]T_2=\frac{(95.0 \textdegree C)*(1.58* 2.46 )}{(1.05 * 4.25 )}[/tex]

Solve inside the parentheses.

[tex]T_2= \frac{(95.0 \textdegree C)*3.8868}{4.4625}[/tex]

[tex]T_2= \frac{369.246}{4.4625} \textdegree C}[/tex]

[tex]T_2 = 82.74420168 \textdegree C[/tex]

The original values of volume, temperature, and pressure all have 3 significant figures, so our answer must have the same. For the number we calculated, that is the tenths place. The 4 in the hundredth place to the right tells us to leave the 7 in the tenths place.

[tex]T_2 \approx 82.7 \textdegree C[/tex]

The temperature is approximately 82.7 degrees Celsius.

To express very large or very small numbers, scientists use what

Answers

Scientists use Scientific notation

will mark brainliest if correct
Which methods separate a mixture according to the size of the particles?

a
filtration and chromatography
b
distillation and chromatography
c
filtration and evaporation
d
distillation and evaporation

Answers

Answer:

filtration and chromatography

Explanation:

I hope this will help you :-)

THIS IS URGENT meant to be due today can someone help out please I’ll brainlist :)!

Answers

Hi,

These are the answers

•Question 6. B, Yogurt and sour milk

•Question 7. B, turn litmus paper red

•Question 8. B, used to find pH of a solution

•Question 9. A, names of products and reactants of a chemical reaction in words

•Question 10. B, feel slippery

Hope it help you. Pls mark brainliest if it helped you

What is the change of state in which a gas becomes a liquid?

Answers

Answer:

Condensation

Explanation:

Answer:

Condensation

Explanation:

When a gas changes to a liquid it is known as condensation. It happens when molecules in a gas slowly reduce their movement speed.

HOPE THIS HELPED

Which of the following statements about alcohols is false?
A. Ethanol is soluble in water.
B. Ethanol has a higher boiling point than ethane.
C. Ethanol produces hydrogen when it burns.
D. None of these

Answers

Answer:

It's C. Ethanol produces hydrogen when it burns

When burned, ethanol produces water and CO2.

there are 3 isotopes of the element Gz: Gz-80,Gz-81,Gz-83. the average atomic mass of Gz is 82.74. what is the most abundant isotope of Gz? (please type the mass number only )

Answers

The most abundant isotope is Gz-83 because the average atomic mass of Gz is closer to 83.

The average atomic mass is defined as the weigthed mean of the isotopes.

The mass of the isotopes is 80, 81 and 83 uma, respectively.

As the average atomic mass (82.74uma) is closer to the atomic mass of Gz-83 than the mass of the other isotopes, you can interpretate that the most abundant isotope is Gz-83.

Learn more about average atomic mass in:

https://brainly.com/question/21536220

!!DUE TODAY, NEED HELP ASAP!!
A student measured the masses of some aluminum and copper cylinders of different volumes. The data is displayed below:
Aluminum: Copper:
Volume (mL)
Mass (g)




Volume (mL)
Mass (g)
3.7
9.99




1.8
16.02
6
16.2




2.3
20.47
8.5
22.99




3.5
31.15
10.74
29




4.2
37.38
15
40.5




5.8
51.62



On graph paper graph the data above on ONE graph. Use the graph paper so the longer side is your y-axis.
Use up the majority of the graph paper. Do not make a small graph!
Use a ruler/straight edge so you graph is neat.
You will need to plot the points for each substance and create a double line graph. When connecting your points for each substance, continue the lines past the plotted points.
Be sure to include a key to identify the substances.
Make your X-axis volume(mL) and your Y-axis mass(g)
Look at the numbers for both substances when creating your scales. You will most likely have a different scale for mass and volume. What is the lowest number? What is the highest number? What does it make sense to go by?

Calculate the density of each metal.

Aluminum:_________________________ Copper:________________________



What happens to the mass of the copper at the volume increases from 6 to 8mL?




Which sample is more dense? How does the graph show you this?

Answers

Answer:  The data are not arranged in a useful pattern.  I arranged them as best I could and made a graph in Excel for demonstration.

Explanation:  The data are plotted with mass on the x axis and volume on the y.  Add a key to identify the top line as CU and the bottom as Al.

The density of Cu is 8.9 g/ml and 2.70 for Al.  

The mass of copper increases by 17.8 grams going from 6 to 8 ml.  (8.9 g/ml)*(2 ml) = 17.8 grams.

Copper is more dense. c The graph shows that for the same volumes, copper has the higher mass.

How many kilojoules are required to raise the temperature of a 150. g sample of silver from 25 °C to 135 °C? Silver has a specific heat of 0.235 J/g °C.

Answers

Answer:

3.8775 kJ

Explanation:

The formula is Q=mcdeltat

We know m (mass) is 150, c (specific heat) is 0.235, and delta t (change in temperature) is 135-25=110

Plug that in and solve for Q

150*0.235*110=3877.5 J

The problem is that this is still in joules so we have to convert to kilojoules

3877.5 J * 1 kJ/1000 J = 3.8775 kJ

nước tự nhiên là chất hay hổn hợp

Answers

nước tự nhiên là chất đó bạn

if you are asked to help the laboratory assistant in separating the mixture which method will you see?​

Answers

Answer:

use secondary data. the normal method to use

If zinc has an atomic number of 30 and a mass number of 65 what is the correct number of protons neutrons and electrons ?

Answers

Answer:

protons 30

neutrons 35

electrons 30

cuantos gramos de soluto y solvente tendra 127 gramos de solición cuya concentración es 14% m/m ayuda para resolverlo

Answers

banetshegtsjegsgeheb

Element Z has 2 natural isotopes. One isotope has a mass of 15.0 amu and a relative abundance of 30%. The other isotope has a mass of 16.0 amu. What is the second isotope's relative abundance?

Answers

Answer:

70%

Explanation:

Just substract 100 % - 30%

4.250 x 10-6 nm in standard form , please help!!

Answers

Answer: 4,250 x 10 - 6

Explanation: ok so we have a decimal number, what you do with that is

[tex]4.250 x 10^{3}[/tex] = 4.250 x 1,000 = 4,250 now you can just move the decimal every time without that equation but its better safe. I'm pretty sure that's how they want it, because its not expanded or word.

can any one tell me same for ALCL3 I need it urgently plzzz ​

Answers

Lets Form bonds

Al=2,8,3

Lets Write actual configuration or modern

[tex]\\ \sf\longmapsto 1s^22s^22p^63s^3[/tex]

It has valency +3Cl:-2,8,7

Let's write configuration

[tex]\\ \sf\longmapsto 1s^22s^22p^63s^23p^5[/tex]

It has valency -1

Now Criss cross valency (Refer to attachment)

We get

[tex]\\ \sf\longmapsto AlCl_3[/tex]

Read the information in the table below:
Reaction
Description Energy to IS break bonds is more tha renergy release to form bonds Energy to break bonds is less than energy release to form bonds
Which type of reaction is represented by B?

Answers

Answer:  Exothermic

Explanation:  The energy of the reactants is leass than that of the products.  Conservation of energy means that the excess is given off, or exothermic.

What makes an atom radioactive?

Answers

Answer:

The unstable nucleus of radioactive atoms emit radiation.

Explanation:

When the atoms of an element have extra neutrons or protons it creates extra energy in the nucleus and causes the atom to become unbalanced and unstable, or radioactive.

(https://www.epa.gov/radtown/radtown-radioactive-atom-activity-4-atomic-stability)

Answer:

When the atoms of an element have extra neutrons or protons it creates extra energy in the nucleus and causes the atom to become unbalanced or unstable. Whether radioactive elements can become stable and if so, how. The unstable nucleus of radioactive atoms emit radiation. ... This process is called radioactive decay.

Explanation:

Help!! due tomorrow













.

Answers

Answer:

It's B. The molecules in the system have more kinetic energy than a solid.

Describe the color change that would be observed in water in left hand beaker

Answers

Answer:

is there supposed to be a photo with this?

Explanation:

A brick has a mass of 100 G and a volume of 25CM3 what is the density of the brick

Answers

Answer:

[tex]\boxed {\boxed {\sf 4 \ g/cm^3}}[/tex]

Explanation:

We are asked to find the density of a brick. Density is a substance's mass per unit volume. The formula for calculating density is as follows.

[tex]\rho= \frac{m}{v}[/tex]

The mass of the brick is 100 grams and the volume is 25 cubic centimeters.

m= 100 g v= 25 cm³

Substitute the values into the formula.

[tex]\rho= \frac{ 100 \ g}{25 \ cm^3}[/tex]

Divide.

[tex]\rho=4 \ g/cm^3[/tex]

The density of the brick is 4 grams per cubic centimeter.

English
M.
3.x - 9
2r-7
.X + 2
18

Answers

Answer:

it will come answer 21 write

How many moles of magnesium bromide are formed when 3.0 moles of magnesium reacts with 2.0 moles of bromine?

Mg+Br2 -> MgBr2

Answers

Answer:

Explanation:

Hello there, I think this is a limiting agent question.

When 3 moles of Mg is reacted with 2 moles of Br2, because of ratio, we just need 1.5 moles of Br2, so Mg is a limiting agent.

So 3 moles of Mg will make 3 moles of MgBr

Answer:

Use the given functions to set up and simplify

Mg+Br2→MgBr⋅2.

3=

2=

Mg+Br2→gBr⋅2=r2B+gM→MgBr⋅2

Explanation:

SORRY IF I AM WRONG HAVE A BLESS DAY :D

name four states of matter​

Answers

Answer:

1. solid

2. liquid

3. gas

4. plasma

Explanation:

In physics, a state of matter is one of the distinct forms in which matter can exist. Four states of matter are observable in everyday life: solid, liquid, gas, and plasma.


If an object has a mass of 43.23 g and a volume of 32.1 mL, what is its density? Show your work!

Answers

Answer:  1.34 g/ml

Explanation:  Density is an objectives mass divided by it's volume:

(43.23 g)/(32.1 ml) =1.34 g/ml

An element has an atomic number of 16. An ion of this element has a 2-charge. How was the ion formed?

Answers

Answer: The answer is ‘a neutral atom gained 2 electrons’

Explanation: Because electrons are negatively charged and adding 2 extra would make the ion negatively charged by 2

Answer:

The answer to all the quiz questions are

Explanation:

1. Which statement describes the number of protons in each atom of an element?

*The number of protons is given by the atomic number, which increases by one moving from left to right across each row of the periodic table.*

2. An element has an atomic number of 16. An ion of this element has a 2– charge. How was the ion formed?

*A neutral atom gained 2 electrons.*

3. Rubidium has an atomic number of 37 and a mass number of 85. How many protons, neutrons, and electrons does an ion of rubidium with a 1+ charge have?

*37 protons, 48 neutrons, and 36 electrons*

4. There are three stable forms of neon: neon-20, neon-21, and neon-22. Which statement is true?

*Their atomic masses differ.*

5. Beryllium has an atomic number of 4. How many neutrons does the isotope beryllium-9 have?

*5*

Magnesium occurs naturally in only three isotopes. ^24 Mg has an isotopic mass of 23.9850 amu and an abundance of 78.99%. ^25 Mg has an isotopic mass of 24.9858 amu and an abundance of 10.00%. Find the mass number of the last isotope of magnesium.

Can someone please explain how to solve this? *done mine the notes*

Answers

Answer:

25,98 amu and 11.01% abundance

Explanation:

1. Find the missing abundance

100 - 78.99 - 10 = 11.01 %

2. Using each mass and abundance and the periodic table for the Mg amu

And let Isotope = Mg

23.9850(78.99%) + 24.9858(10%) + Mg(11.01%) = 24.305 (100%)

Solve for Mg

Mg = 25,98

Density and Years: What do you know?Objectives: determine and compare density of pennies to assess composition. Procedure:1. Read the directions and create a data table accordingly.2. Place 15-20 pennies in order of consecutive dates. Find the mass of each penny and record.3. Find the volume of all 5 pennies by water displacement and record in your data table. Record the volume adding 5 more pennies at a time until you have measured them all (15-20).a. Find the average volume of 1 penny.4. Calculate the density of each penny and graph according to the year.5. If the density of copper is 8.96 g/cm3 what would the mass of a pure copper penny be?6. Draw a conclusion.7. How might this relate to a real world example?

Answers

Answer:I dunno

Explanation:it is the best thing I ever said in this app

Isotope ?-1 has an atomic mass of 1.
99.985% of all atoms of element ? are of this
form.
Isotope ?-2 has an atomic mass of 2
0.015% of all atoms of element ? are of this form.

Answers

Answer: Isotope-1: Hydrogen (H)

Isotope-2: Deuterium (H)

Explanation: The periodic table shows that the smallest element in hydrogen (H), at an average atomic weight of 1.008. Hydrogen-1 has one proton, one electron, and no neutrons, which adds to 1 AMU. Hyrogen-2 is an isotope of hydrogen that contains 1 neutron in addition to the proton, bringing the mass to 2 AMU. It is only at 0.0156% abundance on Earth and is given the name Deuterium, sometimes refered to as "heavy water" when incorporated into a water molecule. A third isotope has 2 neutrons, and is called Tritium.

In your conversion from Milli- to Centi- units, would you move the decimal point to the left or the right?

Answers

Answer:

one unit to the left

Explanation:

cm are 10 times mm, so to convert you have to divide by ten

Examples

100 mm = 10,0 cm

0.50 mm = 0.05 cm

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