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

how to calculate valency of atoms?​

Answers

Answer:

The valency of a molecule is zero.

Explanation:

Valency is calculated by calculating number of electrons present in outermost orbitals of atom of element.

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Sugar C12 H22 011 can be classified as a element, heterogeneous mixure, solution, compound​

Answers

Answer:

The answer is a compound.

it is a compound as it contains different elements

Explanation:

Which of the following are decomposition reactions?
A. CH4 (9) +202 (9) - CO2 (g) + 2H20 (9)
B. N2 (9) + 3H2 (9) ► 2NH3 (9)
C. CaCO3 (s) - Cao (s) + CO2 (9)
D. 2H20 (1) ► 2H2 (9) + O2 (9)

Answers

Answer:

C and D

Explanation:

A reaction is said to be decomposed, if the reactant is broken down to liberate single element.

The 4f subshell of an atom contains 14 electrons. What is the maximum number
of electrons having same spin in it?

Answers

Answer:

I hope it will help you

Explanation:

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What are the answers to these?

Answers

Answer:

1)physical change

Explanation:

2)chemical change

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.

Classify the items based on whether they are or are not matter.

Answers

Answer:

Matter:

toothpaste

gasoline

bacteria

cell

Not matter:

happiness

sound

Explanation:

Matter is something that has mass and volume. Happiness is just a feeling, it doesn't exist in 3d world. Sound is a wave or just the movement of matter (particles of matter). Others have masses and volumes.

What are two factors that can change the rate of a chemical?

Answers

Answer:

the surface area of a solid reactant.

temperature.  

presence/absence of a catalyst.

*
Water vapor deposes into frost. What are the frost particles made of?

Molecules of Hydrogen
Molecules of H2O
Molecules of Oxygen
Molecules of Hydrogen and Molecules of Oxygen

Answers

Answer:

Molecules of H2O

Explanation:

Frost is condensed vapour and vapour is gaseous water. So, their particles are made up of same particles as water, i.e., H2O.

if you have observed something about the world and want to investigate it further, what are you seeking to do?

Answers

I'm seeking to ASK A QUESTION in accordance to the scientific method.

WHAT IS SCIENTIFIC METHOD:

Scientific method is the step by step procedure employed by scientists in order to investigate an occurrence or phenomenon in the world.

The steps involved in the scientific method, which begins with making an observation, are as follows:

Make an observation

Ask a question based on the observation

Formulate a hypothesis

Test the hypothesis via experimentation

Analyze result data

Draw conclusion

According to this question, after observing something about the world and I want to investigate it further by asking a question as the next step.

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How might you separate a mixture of iron fillings and salt?

Answers

Answer:

You use a magnet and the fillings will go with the magnet.

When NaCl is added to a solution of AgNO3, Pb(NO3)2, or Ca(NO3)2, in which case(s) does a precipitate fom?

A. AgNO3 only
B. Pb(NO3)2 only
C. Ca(NO)2 only
D. AgNO3 and Pb(NO3)2

Answers

C could be the possible answer

When NaCl is added to a solution of AgNO₃, Pb(NO₃)₂, or Ca(NO₃)₂,a precipitate will form only in Ca(NO₃)₂ only.

What is double displacement reaction?

In a double displacement reaction, the reacting substances exchange their ions or bonds and form new compounds

In a double displacement reaction, only ionic compounds can take part and  compounds of only those metal reacts which will be almost having equal reactivity.

For example -

Sodium chloride can react with Potassium sulphate to form Sodium sulphate and Potassium chloride.

Barium nitrate can react with Lead sulphate to form Barium Sulphate and Lead nitrate.

Therefore, When NaCl is added to a solution of AgNO₃, Pb(NO₃)₂, or Ca(NO₃)₂,a precipitate will form only in Ca(NO₃)₂ only.

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Place the above in a interrelating concept map include were physical changes and chemical changes would take place list several types of physical changes and chemical changes

Answers

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Hand tools in need of repair or replacement create hazards. Tools with wooden handles, like hammers and axes, can splinter or break in the middle of use, resulting in injury. Impact tools like chisels are unsafe for use if they have “mushroomed” heads because they could shatter on impact and cause injury.

Nguyên tố hoá học là gì

Answers

Nguyên tố hóa học, thường được gọi đơn giản là nguyên tố, là một chất hóa học tinh khiết, bao gồm một kiểu nguyên tử, được phân biệt bởi số hiệu nguyên tử, là số lượng proton có trong mỗi hạt nhân.

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Use you observation to determine which polymorph is in the customer’s returned chocolate sample.

Answers

Cocoa butter, the fat in chocolate, can crystallize in any one of 6 different forms (polymorphs, as they are called). Unfortunately, only one of these, the beta crystal (or Form V), hardens into the firm, shiny chocolate that cooks want. Form VI is also a stable hard crystal, but only small amounts of it form from the good beta (Form V) crystals upon lengthy standing. When you buy commercial chocolate it is in the form of beta crystals.

When you melt chocolate and get it above 94° F, you melt these much desired beta crystals and other types of crystals can set up. If you simply let melted chocolate cool, it will set up in a dull, soft, splotchy, disgusting-looking form. Even the taste is different. Fine chocolate has a snap when you break it and a totally different mouthfeel from the other cocoa butter forms.

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What is the density of a piece of metal with a
mass of 23.5 g and a volume of 11.1 mL? You
will report in units of g/mL. Please answer only
with a number. Include only two decimals in
your answer.

Answers

The density of the piece of metal is 2.12g/mL

HOW TO CALCULATE DENSITY:

Density, which refers to the mass of an object in relation to its volume, can be calculated by dividing mass by volume. That is;

Density (g/mL) = mass (g) ÷ volume (mL)

According to this question, a piece of metal has a mass of 23.5 g and a volume of 11.1 mL, hence, the density can be calculated as follows:

Density = 23.5/11.1

Density = 2.12g/mL

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How do the respiratory system and circulatory system interact? (1 point)
o
In the lungs, carbon dioxide is transferred to the blood and carried by red blood cells. Once it is distributed, the red blood cells
pick up oxygen and transport it back to the lungs, where is transferred to the lungs so it can be exhaled.
O
In the lungs, oxygen is transferred to the blood and carried by red blood cells..Once it is distributed, the red blood cells pick up
carbon dioxide and transport it back to the lungs, where is transferred to the lungs so it can be exhaled
The respiratory system and circulatory system do not interact because the respiratory system is related to breathing and the
circulatory system is related to blood.
O
In the lungs, air is transferred into the blood stream, where red blood cells deliver it to the heart. The heart then separates the
oxygen and sends it to the organs, while sending the waste back to the lungs to exhale.

Answers

Explanation:

The circulatory and respiratory systems work together to circulate blood and oxygen throughout the body. Air moves in and out of the lungs through the trachea, bronchi, and bronchioles. Blood moves in and out of the lungs through the pulmonary arteries and veins that connect to the heart

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what is electric configuration?
write the electric configuration of chlorine..​

Answers

Answer:

The systematic representation for the distribution of electrons in different energy levels of an atom or orbital of an atom is called electronic configuration .

The electronic configuration of chlorine is 1s^2,2s^2,2p^6,3s^2,3p^6

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what is a complex permanent tissue? mention the major functions of this tissue .​

Answers

Answer:

Complex permanent tissue is defined as a collection of structurally dissimilar cells performing a common function or set of functions.

its functions are:

1.help in the transportation of organic material, water, and minerals up and down the plants.

2.it helps in transportation of food from leaves to other parts of plants.

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What is the energy of a light wave with a frequency of 9.8 x 10^20 Hz?

Answers

Answer:

Regions of the Electromagnetic Spectrum

Wavelength (m)Frequency (Hz)Radio> 1 x 10-1< 3 x 109Microwave1 x 10-3 - 1 x 10-13 x 109 - 3 x 1011Infrared7 x 10-7 - 1 x 10-33 x 1011 - 4 x 1014Optical4 x 10-7 - 7 x 10-74 x 1014 - 7.5 x 1014

My friend asked, Our sale is being used to measure
flour. What was the scale really measuring about
the flour?
A) color of flour
B) volume of flour
C) weight of flour
D) temperature of flour

Answers

The answer is C, the weight of flour

Which of these answers describes a scientific law?
(Pls)

Answers

Answer:

big ablsolty long pp

Explanation:

dong

Why are intensive properties useful for identifying a substance?

a
They are chemical properties.
b
They describe the amount of substance you have.
c
They are physical properties.
d
They do not depend on the amount of substance you have.

Answers

Answer:

d

They do not depend on the amount of substance you have.

Intensive properties useful for identifying a substance because they do not depend on the amount of substance you have.

WHAT ARE INTENSIVE PROPERTIES:

Intensive properties are physical properties of a substance that do not depend on the size or amount of a sample e.g. density, temperature, colour, boiling point etc.

On the other hand, extensive properties are dependent on the size of a substance e. g. mass, volume, weight etc.

Intensive properties of a substance do not change with respect to size, hence, they can be used in the identification of a substance.

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Can someone plz help me plz giving brainliest

Answers

Answer: yes because it talks about what he pacifically he did and what the results was and he would probably need 2 get a little more data

Explanation:

To reduce the costs of extracting aluminum, what must be added to it to reduce the melting point? A. Bauxite B. Cryolite C. Cathode D. Anode

Answers

Answer:

cryolite

Explanation:

B B B B B

cryolite is the answer

What is the Color of potassium heptaoxodichromate (v)

Answers

Answer:

orange

Explanation:

The color of potassium hepaoxodichromate is orange.

Answer:

it's very bright red orange in color.

Explanation:

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Can someone help me?
Which element would have the lowest electronegativity?

an element with a large number of valence electrons and a small atomic radius

an element with a large number of valence electrons and a large atomic radius

an element with a small number of valence electrons and a large atomic radius

an element with a small number of valence electrons and a small atomic radius

Answers

Answer:

an element with a large number of valence electrons and a large atomic radius

Explanation:

Electronegativity means a tedency when an atom attracts bonding electrons in a covalent bond situation.

» If an atom has many valency electrons [ empty orbitals in outermost shell ], it has difficulty in attracting electrons hence electronegativity low.

» If an atom is large, its nuclear attraction force of incoming electrons is low hence low electronegativity.

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The element that would have the lowest electronegativity is an element with a small number of valence electrons and a large atomic radius.

Both electronegativity and atomic radius are periodic trends. Electronegativity increases across the period while atomic radius decreases across a period.

An element that has a small number of valence electrons and a large atomic radius will most likely be a metal hence it will have the lowest electronegativity.

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please help if there are any experts please tell me whhich is correct

Answers

I believe that the answer to your question is letter D, normal line.

Additionally, according to the law of reflection, the angle of incidence is equivalent to the angle of reflection. This means that the angle of reflection is the angle between the normal line and the reflected ray.

I hope that this has helped you. Good day to you.

Consider 81.0 g samples of two different compounds consisting of only carbon and oxygen. Compound 1 consists of 22.1 g of carbon, and compound 2 has 34.7 g of carbon. Determine the ratio in whole numbers of the masses of carbon that combine with 1.00 g of oxygen between the two compounds.

Answers

Answer:

Compound 1:   CO2

Compound 2:  CO

Explanation:

The attachment illustrrates the calculations.  The masses of both C and O are converted into moles of those two elelements and the resulting mole values are taken as ratios of the two elements.  Compound 1 has twice as many moles of O as of C, so it's empirical formula must be CO2.  Compound 2's O/C ratio is 1, so it becomes CO.

985 grams converted to kilometers

Answers

Answer:

?

Explanation:

did you mean kilograms?

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