Please help me thank you!

Answer:

b. independent/manipulated variable

Explanation:

Independent/manipulated variable - refers to the variable that is changed by the scientist or an experimenter. Only one variable that is independent is required to ensure a fair test in an excellent experiment. As the independent variable is being changed by an experimenter or scientist, data is being recorded simultaneously as they are collected.

Charcoal with a carbon-14 activity of 0.60 compared to new wood has less than 5,730 years.

A radioactive isotope is an element in nature that emit radioactivity in a given period of time (e.g., the half-life for C14 is equal to 5,730 years).

Radioactive dating is a technique to measure the age of an element by measuring its radioactive activity.

In conclusion, charcoal with a carbon-14 activity of 0.60 compared to new wood has less than 5,730 yr.

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It is a limitation of the kinetic-molecular theory because closeness and low speed don't allow  intermolecular forces to become important at certain pressure and temperature.

The kinetic gas theory explains micro-particles (atoms and molecules). The kinetic theory is basically  based upon the assumption of microscopic particles . We can use it as a microscopical model.

And the kinetic theory of gases explains how gases behave by assuming that they are made up of quickly moving atoms or molecules.

Basically kinetic model is based on the below assumptions.-

I t is assumed that the gas is made by a large number of identical molecules. And molecules are moving in random directions. And also separated by the large distances as compared to their size.

The molecules collide completely elastically  without no energy loss.

Always kinetic energy is transferred between molecules through heat.

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The chemical equation for photosynthesis is 6CO2+6H2O→C6H12O6+6O2. 6CO2+6H2O→C6H12O6+6O2.

In plants, the process of photosynthesis takes place in the mesophyll of the leaves, inside the chloroplasts.

Photosynthesis is the technique with the aid of which inexperienced plant life and positive other organisms remodel light electricity into chemical strength.

During photosynthesis in green flowers, mild strength is captured and used to convert water, carbon dioxide, and minerals into oxygen and energy-wealthy organic compounds.

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Answer:

The answer is actually:

D

Explanation:

The limiting reactant will be HCl.

They limit the amount of products produced in reactions.

From the equation, the mole ratio of Mg to HCl is 1:1.

Mole of 4.00 g mg = 4/24.3 = 0.1646 moles

Mole of 3.2 g HCl = 3.2/36.458 = 0.0878 moles

Thus, Mg is in excess while HCl is limiting in availability.

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Answer:

HCI , Excess reactant is Mg , and 4.18 g MgCl

The naturally occurring form of a metal that is concentrated enough to allow economical recovery of the metal is known as D)ores.

Ore is natural rock or sediment that consists of one or more valuable minerals, commonly containing metals, that can be mined, handled, and offered at a profit. Ore is extracted from the earth thru mining and treated or subtle, often via smelting, to extract the precious metals or minerals.

Ore is a deposit in Earth's crust of one or greater valuable minerals. The maximum valuable ore deposits include metals crucial to industry and alternate, like copper, gold, and iron. Copper ore is mined for ramification of industrial uses.

Ores are minerals that have a high awareness of a sure detail, commonly metallic. Examples are cinnabar (HgS), an ore of mercury, sphalerite (ZnS), an ore of zinc, cassiterite (SnO2), and an ore of tin (Mineral).

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The theoretical molar yield of lead (II) chloride will be 9 moles.

First, we need to look at the equation of the reaction:

[tex]Pb^{2+} + 2Cl^- --- > PbCl_2[/tex]

From the equation, the 1 mole of Pb2+ ion requires 2 moles of Cl- ion in order to produce 1 mole of lead (II) chloride.

Thus, with 18 moles Cl- ions, 9 moles of Pb2+ would be needed, instead of 12 moles. Pb2+ is simply in excess while Cl- can be said to be limiting.

Therefore, Cl- will determine how much of lead (II) chloride that will be produced. The ratio is 2 moles of Cl- to 1 mole of lead (II) chloride.

With 18 moles Cl-, 9 moles of lead (II) chloride will, thus, be produced.

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The safety data sheet section which includes chemical abstract service number, european commission number and european chemical agency number are section3 and section 1 respectively.

Section 3 lists the ingredients, including stabilizers and contaminants, that are present in the product mentioned on the SDS. Information on compounds, concoctions, and any chemicals where a trade secret is asserted is provided in this section. The following details must be included in this section are Chemical Abstract Service (CAS) number and other unique identifiers.

The Safety Data Sheet(SDS's) compounds are listed in Section 1 along with suggested applications. It also offers the supplier's contact details. This section must have the following information of name, location, contact information, and emergency phone number for the manufacturer, importer, or other accountable party like European commission number and European chemical agency number.  

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When selecting a photometric technique that is more sensitive to a low concentration of analyte, a laboratory director compares absorbance measuring devices against those that measure fluorescence intensity. Fluorescence spectroscopy is considered more sensitive in its measurements.

Spectro-fluorometer works on the above mentioned principle...

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The salt produced by the neutralization of 2CsOH(aq) and H₂SO₄(aq) is Cesium Sulphate - Cs₂SO₄.

The given compounds are

2CsOH - a strong base and H₂SO₄ - a strong acid

When they react with one another, the neutralization takes place and forms a neutral compound Cs₂SO₄ called as a salt.

The reaction is as follows:

2CsOH(aq) + H₂SO₄ → Cs₂SO₄ + H₂O

Therefore, the salt produced will be Cs₂SO₄(Cesium sulphate).

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1. The empirical formula of the hydrocarbon is CH₃

2. The molecular formula of the hydrocarbon is C₂H₆

Mass of C = (12 / 44) × 1.47

Mass of C = 0.4 g

Mass of H = (mass of compound) – (mass of C)

Mass of H = 0.5 – 0.4

Mass of H =0.1 g

Divide by their molar mass

C = 0.4 / 12 = 0.03

H = 0.1 / 1 = 0.1

Divide by the smallest

C = 0.03 / 0.03 = 1

H = 0.1 / 0.03 = 3

Thus, the empirical formula of the compound is CH₃

Molecular formula = empirical × n = mass number

[CH₃]n = 30

[12 + (3×1)]n = 30

15n = 30

Divide both side by 15

n = 30 / 15

n = 2

Molecular formula = [CH₃]n

Molecular formula = [CH₃]₂

Molecular formula = C₂H₆

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The number of moles (n) of O2 will be double if atmospheric pressure was doubled and all other variables stayed the same.

The general gas equation, often known as the ideal gas law, is the equation of state for a fictitious ideal gas. It has a number of limitations, but it provides a decent approximation of the behavior of numerous gases under various circumstances.

Applying the law of ideal gas: PV = nRT.

where,

P= pressure of the gas in the atm.

V= volume of the gas in L.

n = no. of moles of the gas in mol.

R = Universal gas constant,

T = temperature of the gas in K.

If V and T are constant and have different values of P and n:

(P₁n₂) = (P₂n₁).

P₂ = 2P₁,

∴ n₂ = (P₂n₁)/(P₁) = (2P₁n₁)/(P₁) = 2n₁.

therefore if we double the pressure then no. of the moles of O2 will be doubled.

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Answer:

A. a compound that donates protons

Explanation: According to the Brønsted-Lowry definition, an acid is a substance that can donate a proton (H+ ion) to another molecule. A base is a substance that can accept that donated H+. After the Brønsted-Lowry acid donates its proton, it becomes the conjugate base of the acid.

Answer:

A: a compound that donates protons.

Explanation:

please give me brainiest.

Answer:

an acid +metal =salt +hydrogen

Explanation:

HCL+Mg =Mgcl2+H2

(because Mg has an ion with a +2 charge ,it attracts Cl with a -2 charge )

therefore the correct answer is D for the above reasons

Answer:

When magnesium reacts with hydrochloric acid (HCl), a single-replacement reaction occurs. These reactions involve the substitution of one element in a compound with another. In this case, the hydrogen in HCl will be swapped with the magnesium metal because both of these elements make cations (positively-charged ions) when they participate in ionic bonding.

So why does the chorine have a subscript of 2 when it bonds with magnesium? This occurs in order to balance the ionic charges and make the overall compound neutral.

Magnesium wants to give away 2 electrons when it ionizes, forming the cation Mg²⁺. However, chlorine only wants to gain 1 electron to fill its valence shell, making it form the anion, Cl⁻. As you can see, if just one of each ion were to bond, the compound would have an overall charge of +1 because (+2 - 1 = +1). Therefore, the compound can be made neutral if two chlorine ions bond with just 1 magnesium ion (+2 - 1 - 1 = 0).

The hydrogen ion from HCl becomes H₂ after the reaction occurs. This occurs because hydrogen generally exists as a diatomic compound in nature (diatomic = exists as 2 atoms).

The complete balanced equation for the reaction is:

Mg + 2 HCl  ------> MgCl₂ + H₂

Answer:

d. Transition metal

Explanation:

A transition metal is an element which has an atom or forms an ion with a partially-filled d-subshell.

As we can see from the electronic configuration of Copper 2+ ion, Cu²⁺:

[tex]_{27}Cu^{2+} = 1s^2\space\ 2s^2 \space\ 2p^6 \space\ 3s^2 \space\ 3p^6 \space\ 3d^9[/tex] ,

copper forms an ion with an incomplete d-subshell that contains 9 electrons; therefore copper is a transition metal.

• Option a. is wrong because copper is not a metalloid. Metalloids have characteristics of both metals and non-metals; copper only has metallic properties.

• Option b. is wrong because 'alkaline earth metals' are the elements in Group 2 of the periodic table; copper is in Group 11.

• Option c. is wrong because 'alkali metals' are in Group 1 of the periodic table.

The new volume of the hydrogen gas at s.t.p., [tex]V_{2}[/tex] = 750 dm³

The molar volume of a gas at s.t.p. is 22.4 dm³.

The change in volume gases at different temperatures and pressures are given by the general gas equation given below:

[tex]V_{1}[/tex] = 600 dm³

[tex]P_{1}[/tex] = 950mmHg

[tex]T_{1}[/tex]= 273 K

The new volume of the hydrogen gas at s.t.p., [tex]V_{2}[/tex] is calculated thus:

[tex]V_{2}[/tex] = (950 x 600 x 273)/(760 x 273) = 750 dm³

In conclusion, the volume of a gas changes with temperature and pressure changes.

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The specific gravity of urine:

The specific gravity of 10ml of urine should be greater than the specific gravity of 10ml of distilled water.

What is specific gravity?

The comparison of the densities of solutes and water is done using specific gravity. Therefore, the following equation, where "D" stands for "density," can be used to represent particular gravity:

USG = [tex]\frac{D solutes}{Dwater}[/tex]

There are no units listed for specific gravity. A typical specific gravity value should range from 1.005 to 1.030. Accordingly, urine ought to be only a little bit denser than water. Low specific gravity is one with a value below 1.005, whereas a high specific gravity is one with a value above 1.030.

The density of the sample is increased by the presence of dissolved solutes in urine that are absent from distilled water.

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Hydrometallurgy uses electrical processes.

Hydrometallurgy can be defined as a steel healing method used to gain metals from ores and waste materials with the usage of aqueous media via combining water, oxygen, and other chemical reagents without or with the use of pressurized surroundings.

That is a method of metal or steel compound extraction from ore via pre-remedies that contain the use of a bleaching agent, separation of impurities, and precipitation. It's far used in the extraction of uranium, gold, zinc, silver, and copper from low-grade ores.

In hydrometallurgy, zinc and iron can be used to displace copper from their answer. But to displace zinc, extra reactive metals i.e., metals having decreased reduction potentials than zinc along with Mg, Ca, ok, etc. are required. ... for this reason, copper may be extracted by means of hydrometallurgy but no longer zinc.

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The changes in matter/energy can be classified as follows:

Matter and energy undergo physical, chemical and nuclear changes.

Physical changes are changes in which no new product is formed.

Chemical changes are changes in which no new product is formed.

Nuclear changes are changes in which no new product is formed.

Examples of each of the given changes is as follows:

Therefore, matter/energy undergo changes.

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Alpha particles are identical to Helium Nuclei.

An alpha particle is subatomic particle which consist two protons and two neutrons tightly bound together. Alpha particle is identical to nucleus of helium atom. Alpha particle is a positively charged particle. Alpha particle is also known as Alpha radiation or Alpha ray.

Helium is a chemical element. The symbol of Helium is He. Atomic number of helium is 2. It is a colourless gas. Helium belongs to period 2.

Thus from the above conclusion we can say that Alpha particles are identical to Helium Nuclei.

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C6FeN6⁻³ is the  correct chemical formula for hexacyanoferrate (III) ion.

This contains information about the proportion of atoms present inn a chemical compound.

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if we did not use an excess of the BaCl2 solution it would decrease the mass percentage of sulfate in the unknown sample.

The net precipitation equation would be.

Ba2+(aq) + SO42-(aq)  → BaSO4(s)

If BaCl2 (Ba2+) is not taken in excess then the precipitation would not be completed as some of the sulfate ions would still be remaining in the solution. This would decrease the mass percentage of sulfate in the unknown sample.

If some tiny pieces of filter paper still remained mixed with the precipitate(BaSO4) then the mass of sulfate would increase and it gives a high mass percentage of the sulfate.

mass percentage of sulfate = (mass of sulfate/mass of sample)*100

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The atomic numbers of elements with a filled outermost shell are 2, 10, 18, etc.

What are noble gases?

Noble gases are elements on the periodic table with filled outermost shells.

With filled outermost shells, these elements are not able to react in chemical reactions ordinarily.

These elements include Helium (2), Neon (10), Argon (18), etc.

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The partial pressure of oxygen in the alveoli is about 104 mm Hg, while the partial pressure of carbon dioxide in the alveoli is 40 mm Hg.

The alveoli are tiny air sacs where gaseous exchange takes place between the lung and the bloodstream.

Because oxygen needs to diffuse into the bloodstream while carbon dioxide needs to diffuse out, the partial pressure of oxygen in the alveoli is around 104 mmHg while that of carbon dioxide is 40 mmHg.

With higher partial pressure than in the blood, oxygen from the alveoli will be able to diffuse into the blood. With lower partial pressure than in the blood, carbon dioxide will be able to diffuse from the blood into the alveoli.

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The United States was waiting for all other industrialized countries to adopt it before proceeding.

The big reasons the U.S. hasn't adopted the metric system are simply time and money. When the Industrial Revolution began in the country, expensive manufacturing plants became a main source of American jobs and consumer products so money for the installation of new system.

So we can conclude that the US was waiting for all other industrialized countries to adopt it before proceeding.

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The House of Representatives defeated the bill calling for conversion to metrics in 1974. Option B

The metric system is the most current system of measurement which is generally accepted in the scientific world. It is the system of measurement that is widely reported in scientific literature.

The reason why the United States have not officially adopted the metric system is that the House of Representatives defeated the bill calling for conversion to metrics in 1974.

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The gauge pressure of the oxygen in the tank in atmospheres is 11.46 atm.

The gauge pressure is given as the pressure relative to the ambient atmospheric pressure. The gauge pressure can be calculated as:

Gauge pressure = System pressure - Atmospheric pressure

The system pressure of the 35-liter tank with 18.3 moles oxygen is given as:

Pressure = moles * Rydberg constant * Temperature / Volume

Pressure = 18.3 moles * 0.08 L.atm.mol⁻¹.K⁻¹ * 298 K / 35 L

Pressure = 12.46 atm

The standard pressure is given as 1 atm.

Thus, the gauge pressure of the oxygen in the tank can be:

Gauge pressure = System pressure - Atmospheric pressure

Gauge pressure = 12.46 atm - 1 atm

Gauge pressure = 11.46 atm

The gauge pressure of the oxygen in the tank in atmospheres is 11.46 atm.

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Answer:

The answer is 8.31 atm.

Explanation:

Ideal Gas Law = PV = nRT
(where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin.)

First, convert the temperature from Celsius to Kelvin:

25°C + 273.15 = 298.15 K

Next, plug in the known values into the Ideal Gas Law equation:

P * 35.0 L = 18.3 moles * 8.31 J/mol*K * 298.15 K

Finally, solve for P:

P = (18.3 moles * 8.31 J/mol*K * 298.15 K) / 35.0 L

The pressure is in units of joules per liter. To convert it to atmospheres, divide by the atmospheric pressure in joules per liter:

1 atm = 101,325 Pa = 101,325 J/m^3 = 101.325 kPa

P (in atm) = (18.3 moles * 8.31 J/mol*K * 298.15 K) / (35.0 L * 101.325 kPa)

= 8.31 atm

Answer: B

Explanation:

There is an atom of one type of element and then two atoms of another type of element.