A sample is in the second half-life. What percent of the sample is stable at this point?


A. 12.5%

B. 25%

C. 50%

D. 75%

Answers

Answer 1

Answer:

75%

Explanation:

on edg :)


Related Questions

How are the three intermolecular forces related?

Answers

Explanation:

Intermolecular forces are electrostatic in nature and include van der Waals forces and hydrogen bonds. ... The three major types of intermolecular interactions are dipole–dipole interactions, London dispersion forces (these two are often referred to collectively as van der Waals forces), and hydrogen bonds.May 20, 2018

which event would most likely lead to a thunderstorm giving brainliest

Answers

Answer:

A

Explanation:

Took at test on this and my teacher said it was right, hopefully I remembered right, also I answered ur other question like this I think lol

Will give brainliest

Answers

Answer:

c. both gases have the same number of molecules

brainliest?

what's the formula for na and f , ca and br , mg and O ​

Answers

Answer:

NaF, CaBr2, MgO

Explanation:

Hi! For this problem, you are going to want to look at the charges of the elements in order to write their formulas.

NaF: Na has a charge of +1 and F has a charge of -1. This means that they have a 1:1 ratio and the formula is written as such - NaF.

CaBr2: Ca has a charge of +2 and Br has a charge of -1. For this problem you want to make sure that their formal charge (the charge of the entire molecule) equals 0. This means that the negative charges need to equal the positive charges. Looking at this, you are going to need to Br ions with a charge of -1 to equal one Ca ion with a charge of +2 - CaBr2.

MgO: Mg has a charge of +2 and O has a charge of -2. This means that they have a 2:2 ratio which simplifies to a 1:1 ratio and the formula is written as such - MgO.

Hope this helps!

What would have a higher boiling point water or hydrocarbon ( from penny liquid stacking)

Answers

Answer:

Im pretty sure its hydrocarbon

Explanation:

What else is produced when sodium carbonate decomposes?
Na2Co3 - Na2O+

Answers

Answer:When a single compound breaks down into two or more compounds or elements in a chemical reaction then it is known as decomposition reaction.

The chemical symbol for sodium carbonate is .

The decomposition of sodium carbonate is:

The decomposition of sodium bicarbonate,  will result in the formation of sodium oxide,  and carbon dioxide, .

Hence, carbon dioxide,  will produce with sodium oxide,  on decomposition of .

Explanation:Na2CO3 Na2O +CO2   CO2 is the answer

Your skin is an important organ and has several functions. All of the functions below are performed by the skin EXCEPT
A)
makes vitamin D.
B
prevents-dehydration:
C)
maintains body temperature.
D)
works with bones to help you move.

Answers

Answer:D

Explanation:

Your skin makes vitamin D

Your skin prevents dehydration

And your skin maintains body temperature. So you are left with D

Answer:

The correct option is D.

works with bones to help you move

Explanation:

Skin is the outer layer of the body and it is the body's largest organ.

It protect the body from heat and other harmful substances.

It is comprises of three layers;

The Epidermis which is the outer layer.

The dermis which is a fibrous later that protect the Epidermis.

The subcutis is the subcutaneous layer that is beneath the dermis.

Function of the skin.

1. It's regulate body temperature

2. It's protect the body from heat and pathogenic entry.

3. It produces vitamin D

4. The skin allow sensations or feelings of touch, heat, and cold.

Therefore;

works with bones to help you move is wrong because it is the muscle that work with the bone.

In the acetylene torch, acetylene gas (C2H2)(C2H2) burns in oxygen to produce carbon dioxide, water, and energy: 2C2H2(g)+5O2(g)⟶Δ4CO2(g)+2H2O(g)2C2H2(g)+5O2(g)⟶Δ4CO2(g)+2H2O(g) You may want to reference (Pages 241 - 243) Section 7.7 while completing this problem. Part A How many moles of O2O2 are needed to react with 1.85 molmol of C2H2C2H2? Express your answer to three significant figures and include the appropriate units. nn(O2O2) = nothingnothing SubmitRequest Answer

Answers

Answer:

4.63 mol

Explanation:

Step 1: Write the balanced complete combustion reaction of acetylene

2 C₂H₂(g) + 5 O₂(g) ⟶ 4 CO₂(g) + 2 H₂O(g)

Step 2: Establish the appropriate molar ratio

According to the balanced equation, the molar ratio of C₂H₂ to O₂ is 2:5.

Step 3: Calculate the number of moles of O₂ needed to react with 1.85 moles of C₂H₂

We will use the stoichiometric molar ratio.

1.85 mol C₂H₂ × (5 mol O₂/2 mol C₂H₂) = 4.63 mol O₂

How is the kinetic energy of the particles of a substance affected during a phase change?
A.) Kinetic energy increases during exothermic changes and decreases during endothermic changes.
B.) Kinetic energy decreases during exothermic changes and increases during endothermic changes.
C.) Kinetic energy does not change, but the potential energy does.
D.) Kinetic energy changes in the opposite way that the potential energy changes.

Answers

Answer: A. Kinetic energy increases during exothermic changes and decreases during endothermic changes

Explanation: During an exothermic change potential energy is converted to kinetic energy. I hope this is correct. :)

Answer:

C

Explanation:

you have a friend who is using a recipe for flat from american cookbook you notice that he set your over temperature at 175F° what you advise him to do?​

Answers

Answer:

I will give them advice, that do the power of flame low....

Explanation:

thanks.

fill in the blank please

amino acids as _____ are to words

Answers

Answer:

Sentences are where there is a beginning and an end of a section of a paragraph. Letters are individual parts of sentences.

The answer that would make the MOST sense would be SENTENCES

Spheres of Earth Assignment Active Analyzing Sphere Interactions Explain how Earth's spheres may be affected by the droughts brought on by El Niño. Sometimes, the surface of the Pacific Ocean warms up, causing changes in the weather in some areas. This phenomenon is called El Niño. El Niño causes the amount of rainfall in some parts of the United States and South America to increase. It also causes droughts to occur in Southeast Asia and Australia. Droughts occur when an area receives less rain than it normally does over a certain period.


help me on this question please. it is 7th grade science​

Answers


During El Niño, changes in wind and ocean current patterns result in warm waters stretching across the whole Pacific Ocean. This extra heating causes changes in wind patterns, which causes atmosphere to react and change all the way from the ground to the edge of space around Earth.

Two models of the same compound are shown.

On the left labeled Model A 2 large overlapping black spheres with 3 small blue spheres overlapping the rear black sphere and 2 medium red spheres overlapping the front black sphere. One of the red spheres has a small blue sphere overlapping it. On the right labeled Model B 2 C's connected by a black line. The C on the left has 3 H's attached by 1 black line each and the C on the right has 2 Os attached to it. The top O is attached by 2 black lines and the bottom O by 1 black line. The bottom O also has an H attached to it by 1 black line.
In what way is Model A better than Model B?

Model A shows the types of elements in the compound, but Model B does not.
Model A shows the total number of atoms in the molecule, but Model B does not.
Model A shows the three-dimensional shape of the molecule, but Model B does not.
Model A shows the number of atoms of each element in the molecule, but Model B does not.

Answers

MODEL A SHOWS THE 3D SHAPE OF THE MOLECULE, BUT MODEL B DOES NOT.

Answer: C. Model A shows the three-dimensional shape of the molecule, but Model B does not.

Explanation:

i took the test and it makes the most sence for the modeles.

4.which is a product of the process shown above?
a. carbon dioxide
b. sugar
c. sunlight
d. water

5.where does the energy that drives this process come from?
a. oxygen
b. sugar
c. sunlight
d. water

Answers

Answer:

4. b 5.C

Explanation:

Photosynthesis makes sugar for plants and sunlight is the energy used to convert CO2 and water into glucose

The product of the process of photosynthesis is sugar and the energy to dive the process of photosynthesis comes from sunlight.

What is photosynthesis?

Photosynthesis is defined as a process by which plants and other photosynthetic organisms convert the light energy in to chemical energy  through the process of cellular respiration.

Some of the energy which is converted  is stored in molecules of carbohydrates like sugar and starches  which are made up of from carbon dioxide and water . Photosynthetic organisms which can perform photosynthesis  are algae and cyanobacteria. Photosynthesis is largely responsible for producing and maintaining the content of oxygen in earth's atmosphere.

The process begins with proteins absorbing light energy  which are called reaction centers and contain a green pigment which is called chlorophyll . In plants ,these pigments are present inside organelles called chloroplasts while in bacteria they are present in plasma membrane.

Learn more about photosynthesis,here:

https://brainly.com/question/26494694

#SPJ2

Question 1 / 1
Which of the following is a covalent bond?
A. CO2
B. NaCl
C. Fe2O,

Answers

Answer:

Chemistry deals with matter, and there is a tremendous variety of matter in the universe. The behavior of matter depends on the type of elements that are present and on the structure of those elements—how they are connected to make a molecule. In this exercise, you will evaluate some representative models to develop the rules used to classify a compound, to predict the formula of a compound, and to name the compound. This exercise is just the beginning of the work needed to be done to master the rules of writing formulas and nomenclature. Your textbook has tables of the names and formulas of common cations and anions, and discusses the rules of nomenclature in detail. You will need to spend some time with this material, as the formal rules of nomenclature may not be presented in lecture, although they will certainly be used in discussions of Lewis structures and reaction chemistry.

Explanation:

In a covalent compound, valence electrons are shared between the two atoms in the bond. These can be evenly shared (covalent bond) or unevenly shared (polar covalent bond). In an ionic bond, electrons are localized to one of the atoms (giving it an overall negative charge), while the other atom has an overall positive charge. The difference in electronegativity between the two atoms in the bond can help predict whether the bond is likely to be ionic, covalent, or polar covalent, as can the type of atoms involved (metals or non-metals). A bond with two identical atoms is always pure covalent, while a covalent bond with two different atoms is likely to be polar covalent.

Show the calculation of the molality of a solution made by dissolving 15.9 grams of Ca3(PO4)2 in 400 grams of water.

Answers

The molality of a solution : 0.128 m

Further explanation

Given

15.9 g of Ca3(PO4)2 in 400 grams of water.

Required

The molality

Solution

molality = mol solute / kg solvent

solute= Ca3(PO4)2(MW=Molecular Weight: 310.2 g/mol)

mol solute :

[tex]\tt \dfrac{15.9}{310.2}=0.0512[/tex]

The molality :

[tex]\tt \dfrac{0.0512}{0.4~kg}=0.128~m[/tex]

HELP ASAP DUE IN 5 MINUTES WILL GIVE BRAINLIEST
Energy is conserved within a system, meaning that forms of energy are either transferred or transformed as they interact with objects. Which of the statements below correctly describe how energy is transferred or transformed in daily life?
Group of answer choices

Kinetic energy transforms into thermal energy when a heating pad is turned on.

Electrical energy is transferred into light energy so that a flashlight generates light when it’s turned on.

Chemical energy in food is transformed into mechanical energy as our body rides a bicycle down the street.

Nuclear energy is transferred to electrical energy to provide electricity for our homes.

Answers

Answer:

i do believe it is C. Chemical energy in food is transformed into mechanical energy as our body rides a bicycle down the street. but if i am wrong plz don't come at me but i believe that is right

Explanation:

Answer:

i do believe it is C. Chemical energy in food is transformed into mechanical energy as our body rides a bicycle down the street. but if i am wrong plz don't come at me but i believe that is right

Explanation:

How many moles of copper are in 6,000,000 atoms of copper?

Answers

Answer: There will be 9.9632 × 10⁻¹⁸ moles of Copper in 6,000,000 atoms of Copper.

If 33.9g NaCl are mixed into water and the total mass is 578g, what is the CHANGE in freezing if Kb= - 1.82C/M (molal)? Assume NaCl does not dissociate in solution.

Answers

Answer:

-1.82 °C

Explanation:

Step 1: Given data

Mass of NaCl (solute): 33.9 gMass of water (solvent): 578 g = 0.578 kgFreezing point depression constant for water (Kb): -1.82 °C/m

Step 2: Calculate the molality of the solution

We will use the following expression.

m = mass of solute / molar mass of solute × kg of solvent

m = 33.9 g / 58.44 g/mol × 0.578 kg

m = 1.00 m

Step 3: Calculate the freezing point depression (ΔT)

The freezing point depression is a colligative property that, for a non-dissociated solute, can be calculated using the following expression:

ΔT = Kb × m

ΔT = -1.82 °C/m × 1.00 m

ΔT = -1.82 °C

Elisa feels tired because she has a condition that affects whether the right molecules are getting to her cells. If her body were functioning correctly, this is what would happen with oxygen:

Answers

Answer:

It would be working properly and providing her energy for her daily activities.

Explanation:

Hello!

In this case, since her oxygen is actually working properly, it is going to be travelling throughout her entire body (via blood) and therefore carbon dioxide would be released as the exhalation product due to cellular respiration carried out in the alveoli which provides energy for her daily activities.

However, the intrusion of different molecules to oxygen into her cells may affect the rate at which cellular respiration is carried out and therefore she may feel tired because such process provides energy to the body.

Best regards!

How many grams are in 2.3 x 1024 formula units of KNO3?

Answers

Answer:

390 g KNO₃

General Formulas and Concepts:Chemistry

Atomic Structure

Reading a Periodic TableUsing Dimensional AnalysisAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Math

Pre-Algebra

Order of Operations: BPEMDAS

Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right Explanation:

Step 1: Define

2.3 × 10²⁴ formula units KNO₃

Step 2: Identify Conversions

Avogadro's Number

Molar Mass of K - 39.10 g/mol

Molar Mass of N - 14.01 g/mol

Molar Mass of O - 16.00 g.mol

Molar Mass of KNO₃ - 39.10 + 14.01 + 3(16.00) = 101.11 g/mol

Step 3: Convert

[tex]2.3 \cdot 10^{24} \ formula \ units \ KNO_3(\frac{1 \ mol \ KNO_3}{6.022 \cdot 10^{23} \ formula \ units \ KNO_3} )(\frac{101.11 \ g \ KNO_3}{1 \ mol \ KNO_3} )[/tex] = 386.172 g KNO₃

Step 4: Check

We are given 2 sig figs. Follow sig fig rules and round.

386.172 g KNO₃ ≈ 390 g KNO₃

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