Need help with #1 and #2

Need Help With #1 And #2

Answers

Answer 1

Answer:

To calculate half life, divide original value by 2.

1.

FOUR HALF LIVES = divide original value by 2, 4 times.

40÷ 2 = 20

20 ÷ 2 = 10

10 ÷ 2 = 5

5 ÷ 2 = 2.5g

2. AFTER TEN DAYS (TWO HALF LIVES)

140 ÷ 2 = 70

70÷ 2 = 35g

AFTER TWENTY DAYS (FOUR HALF LIVES)

140 ÷ 2 = 70

70 ÷ 2 = 35

35 ÷ 2 = 17.5

17.5 ÷ 2 = 8.75g


Related Questions

Assume that wave B has a wavelength of 415 nm. Calculate the frequency of the wave. The value for c is 3.00 x 10 8 m/s. The wavelength of wave A is [__________]Hz.

Answers

The wave B has wavelength of 415 nm. The value for c is 3.00 x 10 8 m/s. The frequency is 7.22 x 10¹¹ Hz.

What is frequency?

Frequency is defined as the number of waves passing through a fixed point in a given amount of time.

The frequency can also be defined as a repeated event is the number of occurrences per unit of time.

Frequency can be expressed as

f = c / ∧

Where c = 3.00 x 10⁸ m/s

           ∧ = 415 nm

So, f = 3.00 x 10⁸ m/s x 415 nm

      f = 7.22 x 10¹¹ Hz.

Thus, the wave B has wavelength of 415 nm. The value for c is 3.00 x 10 8 m/s. The frequency is 7.22 x 10¹¹ Hz.

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Please I will mark brainliest !!! I need both answered

Answers

7 Protons and 7 Neutrons

Find the number of protons, neutrons, and electrons for hydrogen-1, hydrogen-2, and hydrogen-3 respectively.

Answers

Answer:

Protons Neutron Electrons

hydrogen-1 1 0 1

hydrogen-2 1 1 1

hydrogen-3 1 2 1

Explanation:

hydrogen-1, hydrogen-2, and hydrogen-3 are all isotopes.

Isotopes have the same number of protons but a varying number of neutrons. Protons = Electrons.

Hi! I could use some help, I need to turn this in today

Each of these Ionic Compounds are named INCORRECTLY.

1. Find and describe the mistake
2. Correctly name the compound.

CaCl2 - Calcium Chlorine

CuS - Copper Sulfide

Li3P - Trilithium Phosphide

CuBr - Copper(II) Bromide

NaOH - Sodium Hydrogen Oxide

Answers

Explanation:

The nomenclature of ionic compounds is given by:

1. Positive is written first.  And if the metal atom has various oxidation states then its oxidation state is to be mentioned in brackets with help of roman numbers

2. The negative ion is written next and a suffix is added at the end of the negative ion. The suffix written is '-ide'.

1.)  : Calcium chloride  (Correct)

In the given compound, calcium has oxidation state of +2 and chlorine has oxidation state of -1.The name is correct.

2.)  : Copper (II) oxide   (Incorrect)

In the given compound,copper has the oxidation state of +1 and oxygen has oxidation state of -2.So ,the correct name will be Copper (I) oxide.

3.)  : Lead (II) sulfide   (Incorrect)

In the given compound, lead has the oxidation state of +4 and sulfur has oxidation state of -2. So ,the correct name will be Lead (IV) sulfide.

Calcium carbonate decomposes into calcium oxide and carbon dioxide when heated. Calculate the mass of carbon dioxide released when 300 g of calcium carbonate is heated.

Answers

Answer: 131.9 g

Explanation:

Write a Balanced Equation for the decomposition

CaCO₃     →     CaO    +    CO₂

Find Moles of CO₂ Produced

Since the mole ratio of  CaCO₃  to CO₂ is 1 to 1,

the moles of CaCO₃ = moles of CO₂

moles of CaCO₃   = mass ÷ molar mass

                             = 300 g ÷ 100.087 g/mol

                             = 2.997 moles

∴ moles of CO₂ = 2.997 moles

Determine Mass of CO₂

Mass = moles × molar mass

         = 2.997 mol × 44.01 g/mol

         = 131.9 g

∴ when 300 g of calcium carbonate is decomposed, it produces 131.9 g of carbon dioxide.

What does the graph show about the rate of temperature change over time?

Answers

Answer:

The temperature is the same overtime.

Explanation:

Since the line on the graph is straight the temperature will be constant.

If 84.5 mol of an ideal gas occupies 21.5 L at 305 K, what is the pressure of the gas? pressure: atm​

Answers

Answer:

98.367 atm

Explanation:

For this, you must use the equation PV=nRT. Since you are looking for P, rearrange the equation so that P= nRT/V.

Now collect the information you have:

n (mol) = 84.5

R (ideal gas constant to find atm not every case) = .08206

T (temperature) = 305 K (always convert to kelvin)

V (volume in liters) = 21.5

Now Use P= (85.5 mol)×(.08206)×(305 K)/(21.5) to get your answer in atm

Arrange in the correct order of occurrence. Write 1 – 5 for each statement.
___ Magma cools and sinks.
___ Rocks are heated and melt.
___ Magma expands and rises at divergent boundaries.
___ Some magma move sideways in opposite directions.
___ Subduction in convergent boundaries make plates to reach the mantle

Answers

Answer:

Explanation:Rocks are heated and melt.

Some magma move sideways in opposite directions.Magma cools and sinks.Magma expands and rises at divergent boundaries.Magma expands and rises at divergent boundaries.

The electronic configuration of an element is given below.

Element 1: 1s22s22p4

Which statement about the reactivity of the element is true?

It is reactive because it has to gain an electron to have a full outermost energy level.
It is unreactive because it has to lose an electron to have a full outermost energy level.
It is reactive because it has to gain two electrons to have a full outermost energy level.
It is unreactive because it has to gain two electrons to have a full outermost energy level.

Answers

Answer:

It is reactive because it has to gain an electron to have a full outermost energy level.

Explanation:

Answer:

A

Explanation:

true or False
sound needs a medium to travel​

Answers

Answer:

True or T

Explanation:

Is the correct answer please make me brainliest

in structural isomers atoms and functional groups join together in different ways. which of the following statements is not correct with respect to structural isomers

Answers

Structural isomerism is based on the existence of different molecular

structures formed by the same elements.

The statement that is not correct with respect to structural isomers is; All

structural isomers show hydrogen bonding.

Reason:

Structural isomers are isomers that have different molecular structures but

the same molecular formula. They are referred to as constitutional isomers

Therefore;

The empirical formula which is obtainable from the molecular formula is the same for structural isomers.The structural formula of structural isomers are differentStructural isomers that are functional isomers have different chemical properties.

However;

Structural isomers that are linkage isomers may not have hydrogen bonding.

Therefore, the statement that is not correct with respect to structural isomers is; All structural isomers show hydrogen bonding.

 

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The question options are;

The same empirical formula among structural isomers.

Different physical and chemical properties can be possessed by structural isomers.

Structural isomers have different structural formulas.

Hydrogen bonding is shown in all structural isomers.

All the above statements are correct.

what family is hydrogen in? explain

Answers

Explanation:

Hydrogen is a very special element of the periodic table and doesn't belong to any family. While hydrogen sits in Group I, it is NOT an alkali metal.

which physical quantity is not used when determining the stoichiometry in this experiment?

Answers

The physical quantity that is not used when determining the stoichiometry in this experiment is temperature.

Stoichiometry offers a way in which we can calculate the amount of reactants and products using mass - mole relationship. The mass of reactants, number of moles of reactant, mass of product and mass of precipitate can all be used to determine the stoichiometry.

However, the temperature of a reaction is not used to determine the stoichiometry of the reaction.

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Which physical quantity is NOT used when determining the stoichiometry in this experiment?

mass of precipitate mass of product moles of reactant temperature

what are homologous series

Answers

Answer :


A homologous series is a family of hydrocarbons with similar chemical properties who share the same general formula. We will look at three hydrocarbon series: alkanes, alkenes and the cycloalkanes. Hydrocarbons are compounds that contain only hydrogen and carbon.



Answer:

A homologous series is a series of compounds with the same general formula, usually varying by a single parameter such as the length of a carbon chain. Compounds within a homologous series typically have a fixed set of functional groups that gives them similar chemical and physical properties.

Give an example of one pro and one con for the use of stem cells in medicine.

Answers

Answer:

pro ca help defeat diseases, con the stem cell might cause harm

Explanation:

The stem cells are used in regenerative medicine to reproduce the body organs and replace the damaged orangs. The disadvantage of stem cells is that it is difficult to culture the stem cells, and they can be transformed into cancerous cells.

What are stem cells?

Embryonic stem cells can be described as pluripotent stem cells derived from the inner cell mass of a blastocyst. Human embryos can reach the blastocyst stage 4 to 5 days post fertilization, at which time they contain 50 to 150 cells.

Isolating the inner cell mass using immunosurgery results in the destruction of the blastocyst, a process that raises ethical issues,  at the pre-implantation stage have the same moral considerations as embryos in the post-implantation stage of development.

Potential uses of stem cells include the treatment of diabetes and heart disease. The cells are being analyzed or studied to be used in clinical therapies, genetic disorders, and cellular/DNA repair. However, adverse effects in the research processes and clinical processes such as tumors and unwanted responses have been reported.

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I have nothing to say hear look at picture sorry

Answers

Answer:

D

Explanation:

Hope it helps :p

what are 5 different bases for birds

Answers

Answer:

adenine, guanine, cytosine, thymine, and uracil

The specific heat of wood is 2.03 J/g.°C. How much
heat is needed to convert 225 g of wood at -15.0°C to
10.0°C?

Answers

Answer:

11419 J/g/ 11.419 KJ/g

Explanation:

H=MCQ

H=225×2.03×(-15-10)

H=225×2.03(25) Note; negative sign is of no use

H=11419J/g

weight is a flawed measure of mass because it....​ PLEASE ANSWER BY 10/30/21 or a. s. a. p.

Answers

Answer:

I believe it's because it's based on gravity

Explanation:

mass is like your true weight while weight is your mass and some equation with gravity. it's been a few years

Plants are able to produce special chemicals at the right time and place.
A: True
B: False
help fast my test is almost due

Answers

Answer:

true

Explanation:

Someone pls help me I will make you brain

Answers

Answer:

Thanks but I already have a brain LOL.

Your answer is D cooler temperatures.

Melting permisfrost actualy is a source of greenhouse gas because it realeses water which could in turn be vaporized eventualy.

What are the factors affecting chemical reaction??? 4 points. ​

Answers

Answer:

Surface areaTemperature Concentration Amount of catalyst used

Số amin bậc một có cùng công thức phân tử C3H9N là

A. 3. B. 1. C. 2. D. 4

Answers

Answer:

A.3

Three primary amines

Ba amin chính

can you make hydroxychloroquine from grapefruit and lemon rinds

Answers

Hydroxychloroquine cannot be made from grapefruit and lemon rinds.

Hydroxychloroquine is not a natural compound, rather it can only be synthesized from quinoline molecule in the laboratories.

During the synthesis of hydroxychloroquine, several sequential chemical reactions and purifications are done.

Hydroxychloroquine is used in the treatment of:

malariasystemic lupus erythematosus, rheumatoid arthritis

But when grapefruit and lemon rinds are boiled in water, a natural chemical compound known as limonene is obtained.

Therefore, hydroxychloroquine cannot be made from grapefruit and lemon rinds,

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Ionic bonds form between which two types of elements?​

Answers

Answer:

Ionic bonds usually occur between metal and nonmetal ions. For example, sodium (Na), a metal, and chloride (Cl), a nonmetal, form an ionic bond to make NaCl.

Explanation:

Answer:

metal and nonmetal ions

Explanation:

Which of the following are products of combustion?



liquid and solid water


newly discovered elements


additional atoms


heat and light

Answers

The answer option which are products of combustion is: D. Heat and light.

In Chemistry, there are five (5) main types of chemical reaction and these include;

Combination reaction.Double-replacement reaction.Decomposition reaction.Single-replacement reaction.Combustion reaction.

A combustion reaction can be defined as an exothermic chemical reaction between physical substances, usually in the presence of oxygen and hydrocarbons to produce heat, light and carbon.

An example of a combustion reaction is the burning of forest trees and plants.

In conclusion, the products of combustion are heat and light.

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Answer:

heat and light

Explanation:

I will make you brainless answer this 1 question pleaaeeee!b​

Answers

The answer is point 3

How much heat is needed to raise the temperature of 100g of an iron from 25°C to
110°C?
(The specific heat of iron is 0.45 J/g∙°C).

Answers

Answer:

382.5J

Explanation:

Use the formula:

E = mcΔθ or Q = mcΔT

m = 100g

c = 0.45 J/g°C

ΔT or Δθ = 110 - 25 = 85°

Sub in the values:

E = 100 × 0.45 × 85

= 382.5J

what type of mixture is formed when black iron filings and yellow sulfur powder black iron filing is formed
Homogeneous
Heterogeneous
Compound ​

Answers

A compound, is the right answer

Answer:

when you heat the blend, you form iron sulfide, a compound

Depending on the ratio, you could form Fe4S3 or fool's gold

Explanation:When iron filings and sulphur powder are mixed and heated they undergo a chemical reaction and form ferrous sulphide (FeS). It is a new substance which has properties entirely different from Fe and S. Therefore, heating of mixture of iron and sulphur powder is a chemical change forming a compoundf

Contrast the cause of the attraction in ionic bonds
and metallic bonds.

Answers

Ionic bonds are held together by the electrostatic force of attraction between ions, whereas a metallic bond is due to the attraction of metallic cations for delocalized electrons.
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