The half-life of oxygen-15 is 124 s. If a sample of oxygen-15 has an activity of 6400 Bq, how many minutes will elapse before it has an activity of 400 Bq?

Answer:

good question

Explanation:

probably because people like to say they know things and help people with "there stress" and think that there helping them but in reality there making it where they have more :)

Answer:

X

Anode

Loses mass

Electrons in the wire flow away from it

Anions from the salt bridge flow toward it

Y

Cathode

Gains mass

Electrons in the wire flow toward it

Cations from the salt bridge flow toward it

Explanation:

A galvanic cell consists of an anode, a cathode and a salt bridge. The cathode is the negative electrode. The cathode increases in mass due to mass deposition. The cathode becomes increasingly negative as the cell reaction progresses, hence cations from the salt bridge flow towards it.

The anode is the positive electrode. It becomes more positive as the cell reaction progresses hence anions from the salt bridge flow towards it. The anode is the electrode where oxidation reaction occurs hence electrons are lost here and flow towards the cathode. The anode looses mass as the cell reaction progresses due to oxidation.

The pH of the solution is approximately 4.84.

To find the pH of the solution, we need to calculate the concentration of hydroxide ions (OH-) and then convert it to the pH scale.

First, let's determine the concentration of hydroxide ions (OH-) using the Kb value and the concentration of pyridine (C5H5N).

Kb = [OH-][C5H5N] / [pyridinium ion]

Since pyridine is a weak base, we can assume that the concentration of pyridinium ion is negligible compared to the concentration of pyridine. Therefore, we can simplify the equation to:

Kb = [OH-][C5H5N]

Now, we can rearrange the equation to solve for [OH-]:

[OH-] = Kb / [C5H5N]

Substituting the given values, we have:

[OH-] = (1.7 x 10^9) / (0.248)

[OH-] ≈ 6.85 x 10^9

Now that we have the concentration of hydroxide ions, we can calculate the pOH:

pOH = -log10([OH-])

pOH = -log10(6.85 x 10^9)

pOH ≈ 9.16

Finally, we can calculate the pH using the relationship between pH and pOH:

pH = 14 - pOH

pH ≈ 14 - 9.16

pH ≈ 4.84

For more such questions on pH visit:

https://brainly.com/question/12609985

#SPJ8

Type #1 Flame symbols are among the WHMIS emblems.

Type 2: Symbols with a flame above a circle.

Exploding bomb symbols are of type 3.

Compressed gas symbols are of type 4.

Corrosion symbols are type #5.

Skull and water the water symbols are type #6.

Exclamation mark symbols are type #7.

Health hazard symbols are type #8.

Because workplaces require a defined technique to detect hazardous items, WHMIS labels are crucial.

The national ’s hazard standard for Canada is the Health And Safety At work System (WHMIS). Hazard categorization, cautionary container labeling, the distribution of safety data sheets, and worker information and training programs are the system's main components.

The U.S. Ohs Hazard Identification Standard and WHMIS are quite similar.

To know more about WHMIS visit:

https://brainly.com/question/28542158

#SPJ1

Changes or mutations in genes can lead to changes in proteins through their impact on the genetic code and subsequent protein synthesis.

Genes carry the instructions necessary for the production of proteins, which are essential for various cellular functions. Mutations can occur spontaneously or due to factors such as environmental exposures, errors during DNA replication, or genetic predispositions.

Mutations can take various forms. Substitution mutations involve the replacement of a single nucleotide base with another, potentially altering the codon sequence in the gene. This change can result in the incorporation of a different amino acid during translation, leading to an altered protein structure and function.

Insertion or deletion mutations involve the addition or removal of nucleotides in the gene sequence. These mutations can disrupt the reading frame, causing a shift in the codon sequence downstream. As a consequence, the resulting protein can have an entirely different amino acid sequence, often resulting in a non-functional or severely impaired protein.

Mutations in regulatory regions of genes can also impact protein production. These regions control gene expression by influencing the binding of transcription factors. Alterations in these regulatory elements can lead to changes in the amount of protein produced, affecting cellular processes.

Overall, mutations in genes can result in changes to proteins by modifying the genetic code. These changes can affect protein structure, function, stability, and interaction with other molecules, ultimately impacting cellular processes, development, and disease susceptibility.

Know more about mutation   here:

https://brainly.com/question/23030726

#SPJ8

Answer: The set of quantum numbers for the electrons in Be atom are (2, 1, -1, 1/2), (1, 0, 0, 1/2), (1, 0, 0, -1/2) and (2, 0, 0, -1/2)

Explanation:

There are 4 quantum numbers:

Berylium (Be) is the 4th element of periodic table having electronic configuration of \(1s^22s^2\)

For first electron:

\(n=1\\l=0\text{ (for s-subshell)}\\m=0\\s=+\frac{1}{2}\)

For second electron:

\(n=1\\l=0\\m=0\\s=-\frac{1}{2}\)

For first electron:

\(n=2\\l=0\text{ (for s-subshell)}\\m=0\\s=+\frac{1}{2}\)

For second electron:

\(n=2\\l=0\text{ (for s-subshell)}\\m=0\\s=-\frac{1}{2}\)

Hence, the set of quantum numbers for the electrons in Be atom are (2, 1, -1, 1/2), (1, 0, 0, 1/2), (1, 0, 0, -1/2) and (2, 0, 0, -1/2)

Considering the definition of molar mass, the correct answer is option c): the mass of 1.85 moles H₂O₂ is 62.9 grams.

The molar mass of substance is a property defined as the amount of mass that a substance contains in one mole.

The molar mass of a compound is the sum of the molar mass of the elements that form it (whose value is found in the periodic table) multiplied by the number of times they appear in the compound.

In this case, you know the molar mass of the elements is:

So, the molar mass of the compound H₂O₂ is calculated as:

H₂O₂= 2× 1 g/mole + 2× 16 g/mole

Solving:

H₂O₂= 34 g/mole

You can apply the following rule of three: If by definition of molar mass 1 mole of the compound contains 34 grams, 1.85 moles of the compound contains how much mass?

mass= (1.85 moles× 34 grams)÷ 1 mole

mass= 62.9 grams

Finally, the mass of 1.85 moles H₂O₂ is 62.9 grams.

Learn more about molar mass:

brainly.com/question/5216907

#SPJ1

The compound has the molecular formula CH₄O. H : O = 1 : 4 : 1 As a result, the empirical formula is CH₄O.

The organic compound sample's mass is 0.5 g, or (0.188 + 0.062 + 0.25) The vapor density should not have a unit.

The organic compound has a molar mass = 16 × 2 g/mol

                                                                            = 32 g/mol

Moles of C atoms = (32 g) × (0.188/0.5) / (12 g/mol) = 1

Moles of H atoms = (32 g) × (0.062/0.5) / (1 g/mol) = 4

Moles of O atoms = (32 g) × (0.25/0.5) / (16 g/mol) = 1

Hence, molecular formula = CH₄O

Thus, the compound has the molecular formula CH₄O. H : O = 1 : 4 : 1 As a result, the empirical formula is CH₄O.

Organic molecules contain covalently bound carbon and hydrogen as well as frequently additional elements. Benzoic acid, diethyl malonate, propanoic acid, butanoic acid, malonic acid, amines, heterocyclic compounds, and benzoic aldehyde are all examples of organic compounds. Organic substances include the carbohydrates, fats (lipids), proteins, and nucleic acids that make up the components of life. Organic molecules include petroleum and natural gas, which constitute the majority of fossil fuels.

Learn more about organic compounds :

brainly.com/question/5994723

#SPJ1

Answer:

Explanation:

Limiting is HCl and excess is Ca(OH)2

excess is 296 grams Ca(OH)2

2 moles H2O will be formed

The question is incomplete, the complete question is;

The rate of reaction was measured during a chemical reaction. After the first 3 seconds, the rate of reaction was 1.8 x10−6 M/s. Which of the following would you expect after another 3 seconds? a

The rate would be higher, and the concentration of reactants would be lower.

b

The rate would be higher, and the concentration of reactants would be higher.

c

The rate would be lower, and the concentration of reactants would be lower.

d

The rate would be lower, and the concentration of reactants would be higher.

Answer:

The rate would be lower, and the concentration of reactants would be lower.

Explanation:

The rate of reaction refers to how quickly or slowly the reactants disappear or the products appear in a given reaction. The rate of reaction depends on the concentration of the reactants. Thus, as concentration decreases with time, the rate of reaction decreases accordingly.

Therefore, reaction rates tend to decrease with time since the concentration of  the reactants decrease with time as the reactants are being converted into products. Thus after three seconds, the rate would be lower, and the concentration of reactants would be lower. Hence the answer above.

Answer:

The rate would be lower, and the concentration of reactants would be higher.

Explanation:

I took the test and i think i got it right

Answer:

The upper and lower limits for the room-temperature thermal conductivity of a magnesium oxide material having a volume fraction of 0.10 of pores that are filled with still air are

Ku = 38.252 W/mK

K lower = 0.199 W/mK

Explanation:

As we know  

Ku = Vp * Kair + Vmagnesium * K metal  

Ku = 0.10 *0.02 + (1-0.25) * 51

Ku = 38.252 W/mK

The lower limit  

K lower = Kmetal* Kair/( Vp * Kmetal + Vmetal * K air)

K lower = (0.02*51)/(0.10*51 + 0.90 * 0.02)

K lower = 0.199 W/mK

Due to the trend of boiling points, the optimal order for elements within a group going from top to bottom is \(A, X_o, Z_w\).

From the given information we can see that the boiling points of the elements decrease from A to Xo to Zw. The highest boiling point (350°C) is of element A, followed by Xo (215°C) and Zw (285°C). We arrange the components in decreasing order of boiling points to get A, Xo and Zw.

It is important to remember that in this situation, the alphabetical order of the elements and their atomic weights are irrelevant considerations. A reasonable basis for arranging the components within the system is provided by the trend in boiling points.

Learn more about boiling points, here:

https://brainly.com/question/1416592

#SPJ1

Answer:0.305g

Explanation:

mass = 79.9x(2.3 x 10^21) / (6.02 x 10^23)

= 0.305

Answer:

2C2H6+7/2O2=2CO2+3H2O

Explanation:

2-c-1 -2

6-H-2-6

7/2*2 =7 2-O-2+1=3-4+1=5-7

sorry, if you don't understand the explanation part. It would be much easier if you could see somebody explaining it and writing it out.

they have videos online to explaining it

Answer:

2 C2H6 + 7 O2 - > 4CO2 + 6 H2o

Explanation:

im sure

Answer:

Rb2O

Explanation:

Rb is a 1+ element and Oxygen is a 2- element. To have a neutral overall charge you must change the molar ratio to have 2 (1+ elements) and 1 (2- element). Together add to 2+(-2)=0. So the overall product is neutral.

123.33mol/L

The formula for calculating the molarity of a solution is expressed as:

Given the following parameters

• Moles, of sucrose (solute) = 0.148 moles

• Litres ,of solution = 0.0012L

Substitute the given parameters into the formula;

Therefore the molarity of this solution is 123.33mol/L.

Answer:

the lymphatic system and the cardiovascular system are the main systems that move fluid throughout the body

Explanation:

The lymphatic system and the cardiovascular system are the two main systems that move fluid throughout the body.

The lymphatic system is a complex network of organs, tissues, and tubes that is a part of the vertebrate body's circulatory system. By removing extra fluid and debris from tissues and depositing them in circulation, the lymphatic system aids in maintaining the body's fluid balance. Providing the body with lymphocytes, and disease-fighting cells also aids in the body's defense against infection.

The human circulatory system is an organ system that transports blood via vessels to and from every region of the body, supplying tissues with nutrients and oxygen while eliminating waste products like carbon dioxide. A muscular heart drives the blood through a closed tubular system. The arterial, capillary and venous components make up the two circuits, the pulmonary and the systemic.

Therefore the lymphatic and the cardiovascular system are the two main systems moving fluid across the body.

Read more about fluid systems, here

https://brainly.com/question/14745480

#SPJ2

Consumers are organisms which depend on the producers or autotrophs for their food and nutrition.

Consumers are also known as heterotrophs, and they feed on the producers (autotrophs or self-feeders or plants) and herbivores (animals that eat plants) for food and energy. They don't produce their own food.

There are four types of consumers:

1) Primary – Herbivores are known as primary consumers and their source of food is plants or the first trophic level of the food chain. Example, Rabbits, Butterflies, Zooplanktons, etc.

2) Secondary – these consumers eat both plants and herbivores and are therefore also known as omnivores. Example, Ants, Crabs, Rats, Humans, etc.

3) Tertiary – these consumers eat primary and secondary consumers. Thus, they can be omnivores as well as carnivores. Example, Hawks, Snakes, Lions, etc.

4) Quaternary – these consumers prey on the tertiary consumers. Example, Polar bear, Alligator, etc.

Learn more about Consumers here:

https://brainly.com/question/13420317

#SPJ9

The density of gold is  19.3 g/ \(cm^{3}\) and the mass of a gold block that measures 10 cm by 3 cm by 3 cm is 1737 gram .

The density is equal to mass divided by volume of the substance .

It can be represented as ,

D= m / V

where D = density = 19.3 g/ \(cm^{3}\)( given )

m = mass = ?

V = volume

Volume can be calculated as ,

Volume = l × b × h =  10 cm × 3 cm × 3 cm = 90 \(cm^{3}\)

where l = length

b = breadth

h = height

Putting the value of density and volume to get the value of mass of the gold block .

So , density can be represented by the formula ,

Density = mass / volume

19.3 g/ = mass / 90

Mass of the gold block = 19.3 g/ \(cm^{3}\) × 90 \(cm^{3}\)  

Mass of the gold block = 1737 gram

learn about gold

brainly.com/question/14669985

#SPJ1

Answer:

a. Ag ---> cannot serve as a sacrificial anode for iron because it is lower than iron in the reactivity series. Hence, it is less reactive than iron.

b. Mg ---> can serve as a sacrificial anode for iron because it is higher than iron in the reactivity series. Hence, it is more reactive than iron.

c. Cu ---> cannot serve as a sacrificial anode for iron because it is lower than iron in the reactivity series. Hence, it is less reactive than iron.

d. Pb ---> cannot serve as a sacrificial anode for iron because it is lower than iron in the reactivity series. Hence, it is less reactive than iron.

e. Sn ---> cannot serve as a sacrificial anode for iron because it is lower than iron in the reactivity series. Hence, it is less reactive than iron.

f. Zn ---> can serve as a sacrificial anode for iron because it is higher than iron in the reactivity series. Hence, it is more reactive than iron.

g. Au ---> cannot serve as a sacrificial anode for iron because it is lower than iron in the reactivity series. Hence, it is less reactive than iron.

Explanation:

Cathodic protection of iron involves using another more reactive metal as a sacrificial anode. The reactivity series of metals arranges metals based on decreasing order of reactivity. The more reactive metals are found higher up in the series while the least reactive metals are found at the lower ends of the series. Thus, metals above iron in the reactivity series can serve as sacrificial anodes by protecting against corrosion, while those lower than iron cannot.

Based on the reactivity series, the following metals can be classified as either a sacrificial anode for iron or not:

a. Ag ---> cannot serve as a sacrificial anode for iron because it is lower than iron in the reactivity series. Hence, it is less reactive than iron.

b. Mg ---> can serve as a sacrificial anode for iron because it is higher than iron in the reactivity series. Hence, it is more reactive than iron.

c. Cu ---> cannot serve as a sacrificial anode for iron because it is lower than iron in the reactivity series. Hence, it is less reactive than iron.

d. Pb ---> cannot serve as a sacrificial anode for iron because it is lower than iron in the reactivity series. Hence, it is less reactive than iron.

e. Sn ---> cannot serve as a sacrificial anode for iron because it is lower than iron in the reactivity series. Hence, it is less reactive than iron.

f. Zn ---> can serve as a sacrificial anode for iron because it is higher than iron in the reactivity series. Hence, it is more reactive than iron.

g. Au ---> cannot serve as a sacrificial anode for iron because it is lower than iron in the reactivity series. Hence, it is less reactive than iron.

The heat of formation, or enthalpy of formation, of a compound, can be found in a reference such as the appendix of a textbook or a thermochemistry table. The heat of the formation of Fe2O3(s) is -824 kJ/mol. It represents the heat change that occurs when one mole of Fe2O3 is formed from its elements under standard state conditions. So the answer is 824 kJ will be released.

The heat of formation, also known as enthalpy of formation, is the heat energy change that occurs when a substance is formed from its element under standard state conditions. It is usually expressed in kJ/mol.

When we are dealing with the combustion of a substance, this value is used to determine how much heat is released or absorbed in the process. In this case, the substance is iron and we need to form Fe2O3.

To find the amount of heat released, we can use the heat of formation value of Fe2O3, which is -824 kJ/mol.

Since the value is negative, this means that 824 kJ of heat is released when 1 mole of Fe is burned to form Fe2O3 under standard state conditions.

It is also important to note that these values are usually provided at a specific temperature, usually at 25 degrees Celsius, and standard pressure.

To learn more about Enthalpy at

https://brainly.com/question/28207573?referrer=searchResults

#SPJ4

Explanation:

faster and the substance will be a gas.

According to the forces of attraction and principles of phase change the substance molecules will move faster and the substance will be a gas.

Forces of attraction  is a force by which atoms in a molecule  combine. it is basically an attractive force in nature.  It can act between an ion  and an atom as well.It varies for different states  of matter that is solids, liquids and gases.

The forces of attraction are maximum in solids as  the molecules present in solid are tightly held while it is minimum in gases as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.

The physical properties such as melting point, boiling point, density  are all dependent on forces of attraction which exists in the substances.

Learn more about forces of attraction,here:

https://brainly.com/question/2122941

#SPJ5

Answer:

hey are the results of many experiments over a long period of time.

Explanation:

Explanation:

Cis and trans regarding isomerism can be known as geometric isomerism.

-----

Both terms are from Latin, and in chemistry they mean:

Cis = indicates that the functional groups are on the same side of some plane.

Trans = conveys that they are on opposing sides.

Answer: OA. The groups are on opposite sides of the double bond.

Answer: Hợp chất CTHH 0 °C 10 °C 20 °C 30 °C 40 °C 50 °C 70 °C

Actini(III) hydroxide Ac(OH)3   0,0022    

Amonia NH3 1176 900 702 565 428 333 188

Amoni azua NH4N3 16  25,3  37,1  

View 42 more rows  

                    hehe