17 OT-
2021
Subject Chemistry Date
7 Evaluate and discuss how do you think
the Number of the Valence electrons
relates to con elements Chemical properties
show many Valence election are found
in the following Atoms.​

Answer:

Schistosoma or blood fluke

Explanation:

Parasitic organisms are defined as the organisms that depends on other organisms body called host for their nutrition and harm the host body.

The given image is of Schistosoma that is commonly known as blood flukes. Schistosoma are flatworms which causes group of infections in humans known as  schistosomiasis. Schistosoma is a water-borne parasite and found in veins near the human intestine.

Hence, the correct answer is "Schistosoma or blood fluke".

Answer:

No

Explanation:

In the hot pack, as the water reacts with the magnesium sulfate, the pack becomes bigger is not an indication that new atoms have been created or produced.

As with all chemical reactions, they all obey the law of conservation of matter which states that "in chemical reactions, matter is neither created nor destroyed but atoms simply recombine".

The reason why the hotpack becomes bigger is because the atoms gain more volume.

Answer:

1) The amount is less than one mole, 2) The jar is not completely filled, 3) We have 0.166 moles of sulfur.

Explanation:

We proceed to respond each question below:

1) Is this amount more or less than one mole?

According to the Avogadro's Number, one mole of an element contains about [tex]6.022\times 10^{23}[/tex] atoms. Given that we have [tex]1.000\times 10^{23}[/tex] atoms, then we conclude that this amount is less than one mole.

2) Place the jar underneath the counter. Was the jar completely filled?

Let suppose that the jar can contain up to a mole of sulfur. Then, we conclude that jar is not completely filled.

3) How many moles do you have?

The amount of moles is determined by dividing the current amount of atoms by Avogadro's Number:

[tex]x = \frac{1.000\times 10^{23}\,atoms}{6.022\times 10^{23}\,\frac{atoms}{mole} }[/tex]

[tex]x = \frac{500}{3011}\,mole[/tex]

We have 0.166 moles of sulfur.

Answer:

5.14mole

Explanation:

Given parameters:

Mass of sodium bicarbonate  = 431.56g

Unknown:

Number of moles  = ?

Solution:

To find the number of moles, we use the expression below:

  Number of moles  = [tex]\frac{mass}{molar mass}[/tex]  

 Molar mass = 84.01g/mol

 Number of moles  = [tex]\frac{431.56}{84.01}[/tex]   = 5.14mole

Answer: 7.80×[tex]10^{22}[/tex][tex]\frac{1}{6.02*10^{23} }[/tex] =.13

Explanation:

The number of moles that are present in 7.80 × 10²² molecules of HCl is 0.13 moles

The number of moles of a substance is defined as the mass of the substance divided by the molar mass of such a substance. Also, one mole of a substance is synonymous and equal to 6.023 × 10²³ Avogadro's number.

Therefore, the number of moles that are present in 7.80 × 10²² molecules of HCl can be computed as:

[tex]\mathbf{=\Big(7.80 \times 10^{22} \times \dfrac{1}{6.02\times 10^{23} }\Big)\ moles}[/tex]

= 0.12956 moles

≅ 0.13 moles of HCl

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Answer:

rain I think

Explanation:

Precipitation mostly relies on the main source water, that is how snow hail, and other cool weather form are created. So rain I may be wrong.

,

Rain is the most common type of precipitation. Therefore, the correct option is option B among all the given options.

Any liquid and frozen water which condenses in the atmosphere then falls to the ground is referred to as precipitation. Rain, sleet, as well as snow are only a few of its various manifestations. Precipitation is one of three main processes that make up the global water cycle, together with evaporation and condensation.

Water vapor in the clouds condenses into increasing-sized droplets of water, forming precipitation. The drips hit the ground when they are sufficiently hefty. The water droplets can freeze to produce ice if a cloud is colder, as it would be at higher elevations. Rain is the most common type of precipitation.

Therefore, the correct option is option B.

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Answer:

Same.

Explanation:

The temperature of each 400mL bucket is about the same as the temperature of the original bucket of paint.

This is because the temperature is an intrinsic property.This means that temperature is independent of the quantity of matter. Therefore, the temperature of paint inside the bucket is not dependent on the amount of paint present.

Answer:

B. Controlled variables

Explanation:

The Dependent sample t-test compares the mean score of measurements in one group to that of another other group. It mainly used when analyzing comparable sample units as it pairs repeatable observations within a time frame.

Controlled variables are factors that are not tested and remain constant. Some examples of controlled variables are temperature, pressure, volume etc

Answer:

c = 0.898 J/g.°C

Explanation:

1) Given data:

Mass of water = 23.0 g

Initial temperature = 25.4°C

Final temperature = 42.8° C

Heat absorbed = ?

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

Specific heat capacity of water is 4.18 J/g°C

ΔT = 42.8°C - 25.4°C

ΔT = 17.4°C

Q = 23.0 g ×  × 4.18 J/g°C × 17.4°C

Q = 1672.84 j

2) Given data:

Mass of metal = 120.7 g

Initial temperature = 90.5°C

Final temperature = 25.7 ° C

Heat released = 7020 J

Specific heat capacity of metal = ?

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT = 25.7°C - 90.5°C

ΔT = -64.8°C

7020 J = 120.7 g ×  c ×  -64.8°C

7020 J = -7821.36 g.°C ×  c

c = 7020 J / -7821.36 g.°C

c = 0.898 J/g.°C

Negative sign shows heat is released.

Answer:

imma go with the answer B

The product in the reaction  [tex]\rm Zn + 2HCl \rightarrow[/tex] is [tex]\rm ZnCl_2 + H_2[/tex]. The correct answer is option D.

A reaction is a process that involves the transformation of one or more substances into one or more different substances.

The reaction between zinc (Zn) and hydrochloric acid (HCl) is a classic example of a single displacement reaction. In this reaction, zinc reacts with hydrochloric acid to produce zinc chloride ([tex]\rm ZnCl_2[/tex]) and hydrogen gas ([tex]\rm H_2[/tex]).

The balanced chemical equation for this reaction is:

[tex]\rm Zn(s) + 2HCl(aq) \rightarrow ZnCl_2(aq) + H_2(g)[/tex]

Therefore, the product of the reaction between zinc and hydrochloric acid is zinc chloride ([tex]\rm ZnCl_2[/tex]) and hydrogen gas ([tex]\rm H_2[/tex]). Option D is the correct answer.

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Answer; the answer is variations

The unit of genetic material that determines how living things look is called variations, look below for more description.

Hereditary variety alludes to contrasts among the genomes of individuals from similar species. A genome is all the innate data — every one of the qualities — of a creature. Hereditary variety is the distinction in DNA successions between people inside a populace.

For example, the human genome contains somewhere close to twenty and 25 thousand qualities.

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Explanation:

Atomic Number :

It only explain number of protons and electrons in nuclous

Atomic Mass :

Atomic mass tell how much neutrons are present in atom.

Answer:

[tex]\underline{ \boxed{atomic \: number = atomic \: mass - neutron \: number}} \\ \underline{ \boxed{atomic \: mass = proton \: number + neutron \: number}} \\ \underline{ \boxed{neutron \: number = atomic \: mass - proton \: number}}[/tex]

Explanation:

[tex] \underline{ \boxed{1}} \\ ATOMIC \: NUMBER = (atomic \: mass \: number\: - neutron \: number \: )\\ (which \: is \: same \: as ) = \: \underline{ \boxed{proton \: number}}\\ \\ \underline{ \boxed{2}} \\ ATOMIC \: MASS = (proton \: number \: + neutron \:number) \\ (is \: same \: as ) = \: \underline{ \boxed{sum \: of \:atomic \: nuclear \: content}} \\ \\ \underline{ \boxed{3}} \\ neutrons = (atomic \: mass \: number - proton \: number) \\ [/tex]

Answer:

Cilindros graduados

Explanation:

Son una herramienta de medición primaria para el volumen de un líquido, y tiene varias marcas hacia arriba y hacia abajo a lo largo del contenedor con incrementos específicos. Los cilindros graduados vienen en muchos tamaños; entre más pequeños sean de diámetro, más específicas serán las mediciones de volumen. Al leer el volumen de un cilindro graduado, notarán que el líquido parece tener una muesca; el líquido alrededor de los bordes será más alto que el líquido en el centro, inclinándose hacia abajo como los lados de un trampolín cuando alguien está parado en el medio. Esto se llama el menisco. Alineen el punto más bajo del menisco con la marca más cercana, manteniendo el nivel del cilindro para leer correctamente el volumen.

Answer:

4.32 [tex]\frac{1}{18.01}[/tex] ×[tex]\frac{22.4}{1}[/tex] = 5.37

Explanation:

22.4 is how many liters per mole. 18.01 is the mass of H2O.

Answer:

12 moles H2O

Explanation:

Your tools of choice for stoichiometry problems will always be the mole ratios that exist between the chemical species that take part in the reaction.

As you know, the stoichiometric coefficients attributed to each compound in the balanced chemical equation can be thought of as moles of reactants needed or moles of products formed in the reaction.

In your case, the balanced chemical equation for this synthesis reaction looks like this

2H2(g]+O 2(g]→2H2O(l]]

Notice that the reaction requires

2

moles of hydrogen gas and

1

mole of oxygen gas to produce

2

moles of water.

This tells you that the reaction produces twice as many moles of water as you have moles of oxygen gas that take part in the reaction.

You know that your reaction uses

6.0

moles of oxygen. Assuming that hydrogen gas is not a limiting reagent, you can say that the reaction will produce

6.0

moles O

2⋅2

moles H

2O1

moles O

2=

12 moles H2O

Answer:

C. Niche

Explanation:

The role of an organism in it's habitat is it's niche.

Answer: A and C

Explanation: because wavelength is the distance over which the wave's shape repeats.

Wave A and wave C have the same wavelength as they have the same distance between the two adjacent crests or troughs. Therefore, option (2) is correct.

The wavelength of the wave can be defined as the distance between consecutive adjacent points of the same phase on the wave. The separation between the two adjacent crests or troughs on a wave is known as wavelength.

The S.I. unit of the wavelength can be represented in meters. Wavelength is a characteristic of both standing waves and traveling waves, as well as other spatial wave patterns.

The frequency of the wave can be demonstrated as the number of oscillations of a wave in 1 second. The international S.I. units of the frequency can be represented as per second or Hertz.

The relationship between wavelength, speed of light (c), and frequency (ν) is: c = νλ

Therefore, wave A and wave B have the same wavelength in the given diagram.

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Answer:

Mosquitos can stand on water because;

A. The mosquito is able to walk on the water due to the attraction between multiple water molecules, creating surface tension

Explanation:

Surface Tension is the surface property of a liquid which is due to the cohesive forces of attraction between its molecules, that enables it to withstand an external shearing force

The molecules in a liquid maintain a cohesive force between adjacent molecules that keeps all the molecules together such that the liquid has a defined volume

On the surface of the liquid, the cohesive forces between the molecules are shared by only between the adjacent molecules and molecules which are under the surface, and therefore, the attraction is much stronger such that the surface of the liquid is in tension, which is called the surface tension of the liquid

Therefore, the mosquito is able to walk on the water due to the attraction between multiple water molecules, creating surface tension.

There are four equivalent best resonance structures of (PO₄)₃ according to the concept of resonance.

The phenomenon of resonance which is also called mesomerism is the ability of the molecules or ions to explain the bonding in them by the combination of several canonical structures.

It is an extension of Lewis structures to describe bonding in chemical species.The resonance structures also include the fractional charges present on the atom .They are capable of of depicting delocalized electrons which are unable to be depicted by single Lewis structure.

Molecules with extended pi system are well defined by resonance hybrids.It is a way of giving description of bonding in certain molecules.When there is passage of electrons through pi structures which are opposing ,resonance occurs.

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Answer:

Lime(Calcium Oxide) is a white solid with strongly basic properties.Lime reacts readily with water to produce slaked lime,which is the chemical compound calcium hydroxide.....

When carbon dioxide gas is passed through or over limewater,it turns milky due to the formation of calcium carbonate.

Answer:

Proton has positive charge (+) and located in nucleus

Electron has negative charge (-) and located in electron cloud

Neutron has neutral charge (0) and located in nucleus

Answer:

metallic bonds.

Explanation:

Generally, compounds that are ductile and excellent conductor of electricity have metallic bonds between them.

These compounds are usually metals.

Answer:

2.35 x 10²³atoms

Explanation:

Given parameters:

Number of moles of Be  = 0.39moles

Unknown:

Number of atoms  = ?

Solution:

To solve this problem:

                1 mole of a substance contains 6.02 x 10²³ atoms

               0.39 mole of Be will contain 0.39 x 6.02 x 10²³ = 2.35 x 10²³atoms

Answer: Western USA.

Answer:

the answer is the question itself

Explanation:

Answer:

Disagree with the suggestion based on the hygroscopic nature of anhydrous magnesium sulfate

Explanation:

Magnesium sulfate in the anhydrous form is a drying agent. A drying agent salts of inorganic compounds that has the capability of absorbing water to become hydrated, when placed in the presence of a wet surface or moist air

Anhydrous magnesium sulfate is therefore hygroscopic such that it absorbs water from the atmosphere and becomes hydrated and increases in size as its volume is increased according to the following chemical equation

MgSO₄(s) + 7H₂O(l) → MgSO₄·7H₂O(s)

The molar mass of anhydrous magnesium sulfate = 120.366 g/mol

The molar mass of the heptahydrate = 246.47 g/mol

Therefore, the mass of the magnesium sulfate doubles when it forms the heptahydrate, and the magnesium sulfate grows bigger.

Answer:

True

Explanation:

An element is pure substance that conatin only one type of atom

Answer:

true

Explanation:

the element hydrogen is made from atom

Answer:

The statement that best describes the use of catalytic converters in automobiles is;

They oxidize hydrocarbons to form less toxic gases

Explanation:

Catalytic converters

A working engine produces some air pollutants which are made due to fuel not completely burnt in the engine, including unburnt gasoline (a hydrocarbon), nitrogen oxides, and carbon monoxide

Carbon monoxide is poisonous to breathe in if present in the air around us, and nitrogen oxides causes acid rain and smog, while hydrocarbon from the gasoline causes smog

The catalyst in the catalytic converters aids in the conversion of the harmful gases produced by the car engine into harmless gases such as the types of gases already existing in the atmosphere and therefore, can be released into the air

The catalysts in the catalytic converter work by either oxidizing some of the harmful gases such as the unburnt hydrocarbons, or by reducing the other harmful gases such as the nitrogen oxides.

Therefore, the statement that best describes the use of catalytic converters in automobiles is that they oxidize hydrocarbons to form less toxic gases

Answer:

b

Explanation:

got it right on test

Answer:

Avogadro proposed that equal volumes of gases under the same conditions contain the same number of molecules, and hypothesis that proved useful in determining atomic and molecular weights and which led to the concept of mole.

Explanation:

"The mole is important because it allows chemists to work with the subatomic world with macro world units and amounts. Atoms, molecules and formula units are very small and very difficult to work with usually. However, the mole allows a chemist to work with amounts large enough to use."

- Source socratic.org

Hope this helped!