Which of the following materials is most effective for stopping gamma radiation? Please explain your answer





single sheet of paper




one cm of water




several cm of lead




single sheet of aluminum foil

Answer: Accepted Theory

Explanation: A scientific theory is an explanation of an aspect of the natural world that can be repeatedly tested and verified in accordance with the scientific method, using accepted protocols of observation, measurement, and evaluation of results. Where possible, theories are tested under controlled conditions in an experiment.

Answer:

D

Explanation:

Answer:

density

Explanation

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Your answer is In Image Provided.

Answer:

True

Explanation:

There are four time zones in the continental United States: Eastern, Central, Mountain and Pacific.

There are four time zones in the continental United States. Hence, option A is correct.

A continent is a large continuous mass of land conventionally regarded as a collective region.

There are actually six time zones in the USA.

The four main ones are Eastern, Central, Mountain, and Pacific Standard Time.

Hence, option A is correct.

Learn more about the continental here:

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Answer:

Instrinsic Solubility, Temperature, and Sample Size.

Answer:

B . Climate

Explanation:

lunch is temporary to diet is long lasting so , weather is temporary and climate is long lasting  

Today's weather is related to climate, where weather indicates the short-term atmospheric conditions and climate represents long-term patterns, similar to a single meal in relation to an overall diet.So,option B is correct.

Today's lunch is related to your overall diet in the same way that today's weather is related to climate. While the individual meal you eat today is a single occurrence that contributes to your dietary pattern over time, today's weather refers to the specific atmospheric conditions present at a given moment. In contrast, the climate refers to the long-term, predictable atmospheric conditions of a specific area. Weather can be considered the short-term variation, just like one meal is to an overall diet, while climate represents the long-term trends in weather patterns, similar to how a diet represents long-term nutritional habits.

Answer:

Explanation:

In a simple pendulum with no friction, mechanical energy is conserved.  Total mechanical energy is a combination of kinetic energy and gravitational potential energy.   As the pendulum swings back and forth, there is a constant exchange between kinetic energy and gravitational potential energy

CO+2 H2=CH3OH

2.85 mol Co x (2mol H2/1 mol Co)=5.70 mol just concert to grams

5.70 mol H2 x (2 g H2/1 mol H2) =11.40 grams of H2

To react with 2.85 moles of CO, 11.4912 grams of hydrogen gas (H₂) are necessary based on the balanced equation 2 H₂ + CO → CH₃OH.

To determine how many grams of hydrogen are necessary to react with 2.85 mol of CO, we need to refer to the balanced chemical reaction equation that hydrogen and CO might participate in. One such reaction is the synthesis of methanol:

2 H₂ + CO → CH₃OH

According to this equation, 2 moles of hydrogen gas (H₂) react with 1 mole of carbon monoxide (CO) to produce methanol (CH₃OH). Therefore, to react with 2.85 moles of CO, we would need 5.70 moles of hydrogen gas (2 x 2.85 moles of CO). To convert moles of hydrogen to grams, we multiply by the molar mass of hydrogen (approximately 2.016 g/mol for H₂).

5.70 moles H₂ x 2.016 g/mol = 11.4912 g of H₂

Thus, 11.4912 grams of hydrogen are necessary to react with 2.85 moles of CO.

Answer:

Gravity and Mass.

Explanation:

The Earth has more mass than the moon and therefore a higher force of gravity. Because the Earth has a higher mass and force of gravity the moon is attracted to it.

Answer:

Intensive properties can be used to help identify a sample because these characteristics do not depend on the amount of sample, nor do they change according to conditions.

Explanation:

Intensive properties are bulk properties, which means they do not depend on the amount of matter that is present. Examples of intensive properties include:

Boiling Point

Density

State of Matter

Color

Melting Point

Odor

Temperature

Refractive Index

Luster

Hardness

Ductility

Malleability

Explanation:

When amount of matter changes in a substance then a physical property that does not change due to this is known as an intensive property.

For example, density, color, boiling point, hardness etc are all intensive properties.

Whereas  property of a substance that changes due to change in amount of matter of a substance is known as extensive property.

For example, temperature, volume etc are all extensive properties.

Hence, we can conclude that given properties are classifies as follows.

Intensive property : color, hardness, boiling point, density, temperature.

Extensive property : length, volume, mass.

the thing that must change Speed

Answer:

The Speed of the object must change in order to keep moving or stop moving so your answer would be A. Only its speed

Explanation:

Answer:

B. They bond identical atoms together

Explanation:

Metallic Bond:  This is the bond that exists among the atoms of the metal.  This is a type of electrostatic attraction between conduction electrons of metallic atom and their positively charged metal ions.

                                        (figure attached)

Example:  

Copper is a metallic element and its atoms consist of metallic bond among their selves.  

Options A, B, D are not correct as all states for a kind of ionic bond formation.

Ionic bond:  

It form by the complete transfer of electron from one atom to other

It is formed among two atoms of different electronegativities.

Also metals are electro-positive and non -metals are electro-negative so they form ionic bond.

Example is NaCl where sodium is a metal and Chloride is non-metal and they from ionic bond.

Answer:

C. They bond identical atoms together.

Explanation:

Answer:

A metallic bond

Explanation:

Answer:

The positions of the planets at the time of birth have influence on a person's life

Kilometer - km - 1,000

Hectameter - hm - 100

Decameter - dam - 10

Millimeter - mm - 0.001

The table provides clear prefix rules.

The prefixes can be used for most (if not all) units such as grams (kg,mg...).

Hello there i hope you are having a good day :) Answer :

Prefix with the base unit meter :   Symbol :        Number of meters  :

. (kilometre)                                       (Km)              =   1000 m

. (Hectometre)                                   (HM)             =   100 m

. (Decameter)                                    (Dam)            =   10 meters

. (Millimetre)                                       (mm)             =   0.001 meters

Hopefully this help you :)

Answer: C. Secondary data

Explanation:

It means that the data that was collected by someone else that is not the scientist, it may include censuses, surveys, data bases or other sort of information. Such data could be collected by different private companies, from organizational records to government departments, as they often collect data for other research purposes and the information is available to be used for other scientific purposes.

A data that is not directly collected or observed by the scientist is called: C. Secondary data.

Data can be defined as a representation of instructions or factual information in a formalized manner, especially as a series of binary digits (bits) or samples that are used by scientist in an experiment or research.

Generally, there are two (2) main types of data and these include:

In Science, a secondary data refers to a type of data that isn't directly collected or observed by the scientist but from a primary source.

Read more on data here: brainly.com/question/25558534

Answer:

Explanation:

                   aCa + bCO₂ +  cO₂ →  dCaCO₃

Chemical reactions obey the law of conservation of matter. The law states that  "matter is neither created nor destroyed in the course of a chemical reaction". From this, we can deduce that the total mass of the products and reactants are equal.

To balance a chemical reaction, we can do so by inspecting the atoms/compounds involved and putting the appropriate coefficients at the back of the reactants and products. For equations in which inspection might not easily work, we can use a mathematical approach.

By inspecting the reaction above, we can easily balance it

Using the mathematical approach:

The coefficients are a,b,c and d. They are needed to conserve the atoms. So:

For Conservation of Ca: a = d                        (i)

                                  C: b = d                       (ii)

                                  O: 2b + 2c = 3d            (iii)

if we assume that a = 1, then d = 1

                               b = 1

                    from (iii): 2c = 3d -2b

                                    2c = 3- (2 X 1)

                                     2c = 1

                                        c = [tex]\frac{1}{2}[/tex]

Therefore we have a = 1

                                  c = [tex]\frac{1}{2}[/tex]

                                  b = 1

                                   d = 1

                              aCa + bCO₂ +  cO₂ →  dCaCO₃

                           Ca + CO₂ + [tex]\frac{1}{2}[/tex]O₂ → CaCO₃

Answer:

A very large amount of energy is produced from a very small mass

Explanation:

Nuclear energy is produced either by fusion or fission. The former is the fusion of lighter atoms into heavier elements while the latter is the splitting of a heavier atom into lighter atoms. Both produce tremendous amounts of energy. Fusion, causes compaction of mass while fission reduces it. Fusion does not produce radioactive particles while fission does (alpha and beta particles and neutrons).

Energy changes during nuclear fission involve the conversion of a very small amount of mass into a large amount of energy, much more than is produced in chemical reactions like burning coal.

Nuclear fission is a process where the nucleus of an atom, typically a heavy element like uranium-235, is split into smaller, lighter nuclei. The correct description of energy changes during nuclear fission is: a very large amount of energy is produced from a very small mass. This is due to the relationship between mass and energy as described by Einstein's mass-energy equivalence formula, E=mc2. When a mole of uranium-235 undergoes fission, there is a small decrease in the total mass of the products compared to the original mass (about 0.2 grams). According to the formula, this 'lost' mass is converted into a vast amount of energy, approximately 1.8 × 1010 kJ per mole. This energy release in nuclear fission reactions far exceeds the energy produced in chemical reactions, such as the burning of coal.

Answer: combining rubber with sulphur

Explanation:

Chemical change is the change in which chemical composition of the substance changes by rearrangement of atoms.

Physical change is a change in which only the physical properties such as size, shape etc change and there is no rearrangement of atoms.

1. Deflating a rubber balloon only decreases the size of balloon and hence is a physical change.

2. Combining rubber with sulphur is vulcanisation in which sulphur forms bonds with rubber and thus is a chemical change.

3. Stretching an elastic rubber band only changes the shape and hence is a physical change.

4. Erasing pencil marks from a page does not involve any rearrangement of atoms and thus is a physical change.

The mass of [tex]\( \text{Al}_2\text{O}_3 \)[/tex] produced is approximately [tex]\( 709 \text{ g} \).[/tex]

To determine the mass of [tex]\( \text{Al}_2\text{O}_3 \)[/tex] produced when 375 grams of [tex]\( \text{Al} \)[/tex] react completely, follow these steps:

Given Reaction:

[tex]\[ 4 \text{Al} + 3 \text{O}_2 \rightarrow 2 \text{Al}_2\text{O}_3 \][/tex]

Steps:

1. Calculate the molar mass of [tex]\( \text{Al} \) and \( \text{Al}_2\text{O}_3 \):[/tex]

Molar mass of Al aluminum: [tex]\( 26.98 \text{ g/mol} \)[/tex]

Molar mass of [tex]\( \text{Al}_2\text{O}_3 \)[/tex] aluminum oxide:

[tex]\[\text{Molar mass of } \text{Al}_2\text{O}_3 = (2 \times 26.98 \text{ g/mol}) + (3 \times 16.00 \text{ g/mol}) = 53.96 \text{ g/mol} + 48.00 \text{ g/mol} = 101.96 \text{ g/mol}\][/tex]

2. Convert the mass of [tex]\( \text{Al} \)[/tex] to moles:

[tex]\[\text{Moles of Al} = \frac{\text{mass of Al}}{\text{molar mass of Al}} = \frac{375 \text{ g}}{26.98 \text{ g/mol}} \approx 13.91 \text{ mol}\][/tex]

3. Use the stoichiometry of the reaction to find the moles of [tex]\( \text{Al}_2\text{O}_3 \)[/tex] produced:

According to the balanced equation, 4 moles of Al produce 2 moles of[tex]\( \text{Al}_2\text{O}_3 \)[/tex]. So:

[tex]\[\text{Moles of } \text{Al}_2\text{O}_3 = \left(\frac{2 \text{ moles } \text{Al}_2\text{O}_3}{4 \text{ moles Al}}\right) \times 13.91 \text{ mol} = 6.95 \text{ mol}\][/tex]

4. Convert the moles of [tex]\( \text{Al}_2\text{O}_3 \)[/tex] to grams:

[tex]\[\text{Mass of } \text{Al}_2\text{O}_3 = \text{moles of } \text{Al}_2\text{O}_3 \times \text{molar mass of } \text{Al}_2\text{O}_3\][/tex]

[tex]\[\text{Mass of } \text{Al}_2\text{O}_3 = 6.95 \text{ mol} \times 101.96 \text{ g/mol} \approx 708.7 \text{ g}\][/tex]

Answer:

Explanation:

In a chemical formula, the oxidation state of transition metals can be determined by establishing the relationships between the electrons gained and that which is lost by an atom.

We know that for compounds to be formed, atoms would either lose, gain or share electrons between one another.

The oxidation state is usually expressed using the oxidation number and it is a formal charge assigned to an atom which is present in a molecule or ion.

To ascertain the oxidation state, we have to comply with some rules:

For example, let us find the oxidation state of Cr in Cr₂O₇²⁻

This would be:  2x + 7(-2) = -2

                          x = +6

We see that the oxidation number of Cr, a transition metal in the given ion is +6.

Answer: it's total charge of something I already forgot

Explanation: finished quiz don't listen to Einstein above me why do u think he got little votes and likes

Answer:

.18 M

Explanation:

1st

The molarity of an aqueous solution (a solution that has water as the solvent) can be found just by remember this one formula = [tex]\frac{mol}{liters}[/tex].

[moles of solute / volume of solution in L]

So, what do we have? From a glance we have the number of solute (Potassium Chromate), that tells us that we need to convert that value that is in grams (g) into...Moles or (mol), we can do that like this

[tex]\frac{3.50 g}{ } \frac{1 mol}{194.19 g}[/tex]

After we cross multiply 3.50 times 1 and then divide by 194.19 - we get this value ⇒ .018 mol (the g cancels, and we keep mol)

(We get the 194.19 from adding up the molecular weight of Potassium Chromate, which is about 194.19 g/mol. In the above equation though, we flipped this, so that 1 mol is in the numerator and the 194.19 is in the denominator; this helps us convert the 3.50 g to moles).

2nd

Now, we just have to remember that 1 liter = 1000 ml. Because its easier for us to use a L instead of "ml" in the molarity formula. So...

100.00 ml = .1 L         ....

(because [tex]\frac{100 ml}{ } \frac{1 L}{1000 ml} = .1L[/tex]

Finally, we just add our (.018 mol and .1 L) into one nice equation (plug the numbers we converted to back in)

[tex]\frac{.018 mol}{.1L} = .18 M[/tex]

Is it clear now?

Answer:

A

Explanation:

All of the other options are ways that could help the environment from the chemicals, but if they just continue to use the chemicals then it would hurt the environment

Final answer:

Environmental problems caused by chemicals often involve contamination of ecosystems and food supplies, with substances like DDT and PCBs serving as examples of harmful environmental alterations.

Explanation:

An environmental problem caused by chemicals can manifest in various forms, including contamination of ecosystems and food supplies with harmful chemical agents. For example, chemicals such as DDT and its breakdown product DDE, or industrial chemicals like polychlorinated biphenyl (PCB), have contaminated food sources and adversely affected the environment. Persistent organic pollutants, introduced into the environment without a natural occurrence or in unnatural ratios, are known to cause environmental alterations, with their full scale of effects being difficult to calculate. This kind of problem highlights the significant role of chemists and chemical engineers in addressing the challenges posed by these substances, fostering environmentally beneficial chemistry and responsible manufacturing practices.

Answer: I believe the question being asked upon is the 5.2.5 Quiz: Interactions in Ecosystems, which the answer would be, by drinking and by eating other living things, or species.

Explanation: Animals rely on rivers, lakes, and streams for water, which is apart of over environment. Furthermore, animals contain nutrients and water. Therefore, the answer would be, by drinking and by eating other living things. As a student, I read the study, or text, the study goes more in depth regarding the answer to this question in pages 11-18. Have a good day, and make sure to study! ♡︎ P.s. Also added a picture!

Answer:Interactions in Ecosystems, which the answer would be, by drinking and by eating other living things, or species.

Explanation:

Answer:

1 is Cardiac muscles

2 is To control body activities through the release of chemicals

3 is Bacteria

Explanation:

Answer:

1. Skeletal Muscles

2. To control body activities through the release of chemicals

3. Parasite

Answer:

- 386.6 kJ/mol.

Explanation:

ΔHrxn = ΣΔHf(products) - ΣΔHf(reactants)

∴ ΔHrxn = ΣΔHf(products) - ΣΔHf(reactants) = [ΔHf(Ca(OH)₂(s)) + ΔHf(H₂)(g)] - [ΔHf(Ca)(s) + 2*ΔHf(H₂O)(l)].

ΔHf(Ca(OH)₂(s)) = - 985.2 kJ/mol, ΔHf(H₂)(g) = 0.0 kJ/mol, ΔHf(Ca)(s) = 0.0 kJ/mol, ΔHf(H₂O)(l) = - 285.8 kJ/mol.

∴ ΔHrxn = ΣΔHf(products) - ΣΔHf(reactants) = [ΔHf(Ca(OH)₂(s)) + ΔHf(H₂)(g)] - [ΔHf(Ca)(s) + 2*ΔHf(H₂O)(l)] = [(- 985.2 kJ/mol) + (0.0 kJ/mol)] - [(0.0 kJ/mol) + 2*(- 285.8 kJ/mol)] = - 386.6 kJ/mol.

Answer:

C. As the temperature increases, the speed of gas molecules increases

Answer:

C. As the temperature increases, the speed of gas molecules increases.

Explanation:

The following are the basic assumptions of the Kinetic Molecular Theory:

So, the right choice is:

C. As the temperature increases, the speed of gas molecules increases.