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Answer:

d). A catalyst lowers the activation energy for a chemical reaction.

Explanation:

From the given choices, it is true that a catalyst lowers the activation energy for a chemical reaction.

The activation energy is the energy barrier that must be overcome before a chemical reaction can occur.

Some reactions have very high activation energy and would not occur without the introduction of a catalyst.

The catalyst brings the reactants into contact by removing the energy deficiency in the system.

Answer:

The oxidation number of metallic copper is zero. In its compounds, the most common oxidation number of Cu is +2. Less common is +1. Copper can also have oxidation numbers of +3 and +4

Explanation:

Answer:

there's two

Explanation:

resolution means:

a decision to do or not to do something

resolution also means:

the quality of being determined

87,000,000

becuase itis

Answer:

1 = 7.5m/s and 2 = 8m/s

Explanation:

For question no. 1

Given

wavelength = 5 m

Frequency = 1.5 Hz

Velocity =?

We have the formula that

Velocity = wavelength * frequency

= 5 * 1.5

= 7.5 m/s

For question no. 2

Frequency = 2 Hz

Wavelength = 4 m

Velocity = ?

We have the formula that

Velocity = wavelength * frequency

= 4* 2

= 8 m/s

Hope it will help :)

Answer:

1. 7.5m/s

2. 8m/s

Explanation: velocity = Wavelength x Frequency so 5m*1.5Hz=7.5m/s and 2Hz*4m=8m/s

Answer:

Last Column is:

Explanation:

98  ,   7.8   ,   371    and     0.98

Answer:

Molarity = 0.28 M

Explanation:

Given data:

Mass of NH₄NO₃ = 18.9 g

Volume of solution = 855 mL (855mL × 1 L/1000 mL = 0.855 L)

Molarity of solution = ?

Solution:

Number of moles of NH₄NO₃:

Number of moles = mass/molar mass

Number of moles = 18.9 g/ 80.043 g/mol

Number of moles = 0.24 mol

Molarity:

Molarity = number of moles of solute  / volume in L

Molarity = 0.24 mol /0.855 L

Molarity = 0.28 M

Answer:

0.28

Explanation:

:D

Answer:

D

Explanation:

there are 5 electrons in the outer shell of the first picture

According to electronic configuration, model 1 shows 5 electrons in the outer shell of the atom.

Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.

Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.

Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.

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Answer:

oc gravitaional

Explanation:

Answer: V₂ = 37.71mL

Explanation: To determine the new volume of Helium gas, use the Combined Gas Law, which states the following relationship among pressure, volume and temperature:

[tex]\frac{P_{1}V_{1}}{T_{1}} =\frac{P_{2}V_{2}}{T_{2}}[/tex]

where index 1 relates to the initial state of the gas and index 2 to the final state of the gas.

Temperature is in Kelvin, so:

T = °C + 273

For this situation, standard pressure is 1 atm. Temperatures will be:

T₁ = 20 + 273 = 293 K

T₂ = 91 + 273 = 364 K

Solving:

[tex]V_{2}=\frac{T_{2}P_{1}V_{1}}{P_{2}T_{1}}[/tex]

[tex]V_{2}=\frac{364*1*85}{2.8*293}[/tex]

[tex]V_{2}=\frac{30940}{820.4}[/tex]

[tex]V_{2}=[/tex] 37.71

The new volume of He gas is 37.71 mL.

Answer:

Explanation:

At higher temperature, the particles of the gas would be more active and vibrate more, or even have greater collisions. Alex can indicate this in the altered model to depict higher temperature.

Consequently, Charles law gives meaning to why there would be an increased volume of gas in the stable pressurized container, if the temperature were to be increased.

I hope this explanation was clear and concise?

Answer:

Electrons are added to atomic orbitals in order from low energy bottom of the graph to high (top of the graph according to the Aufbau principle. Principle energy levels are color coded, while sublevels are grouped together and each circle represents an orbital capable of holding two electrons

Explanation:

Answer:Each lithium atom provides one. You can see that the oxygen atom has eight electrons (6 of its own, and one from each lithium), and the two lithium atoms have two electrons each.

Explanation:

Answer:

regolith

Explanation:

Answer:

Mathematics is used in Physical Science to calculate the measurements of objects and their characteristics, as well as to show the relationship between different functions and properties. Arithmetic, algebra and advanced mathematics may be used.

Explanation:

Answer:i think it is c, it explodes in water because that’s a chemical reaction

Explanation:

Answer:

because the boiling point of water is 100°C the water bath would boil before the substance

Answer:

Specific gravity compares the density of a substance to the density of air.

Specific gravity is compared the density of a substance to the density of water.

Specific Gravity is a dimensionless quantity that can be defined as the ratio of the density of a substance to the density of the water at a particular temperature.

The mathematical formula of the specific gravity can be written as:

Specific gravity = density of substance / density of water

The density of water at 4°C is used as a reference point as water has the highest density of 1000 kg/m³.  Specific gravity or relative gravity does not have any dimension as it is a dimensionless quantity.

Specific gravity is the ratio of a substance’s density to that of water at a specific temperature. The temperature plays an important role in determining the specific gravity of a substance.

Therefore, specific gravity is a characteristic of the substance at a particular temperature and pressure that also affects the specific gravity.

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Answer:

Percent composition tells you which types of atoms (elements) are present in a molecule and their levels. Percent composition can also tell you about the different elements present in an ionic compound as well.ion:

Answer:

Explanation:hey

Answer:

It means your dad is making those chickens cannibal's.......

Explanation:

Answer:

Hes gonna cook those chickens.....

Answer:

na

Explanation:

gggggggggggggggggggggggggg

Cl (chlorine) ion is negatively charged.

Answer:

Combustion

Explanation:

Naphthalene

The burning of naphthalene is one of the more well known school experiments for combustion reactions. This is because naphthalene combustion involves a simple burning reaction which involves simple burning procedures. The reaction involved is represented by the reaction equation: C10H8 + 12 O2 → 10 CO2 + 4 H2O + energy.

In layman's terms, Naphthalene plus oxygen will burn, and produce carbon dioxide and water. This exothermic reaction that involves releasing heat in the form flame and also produces carbon dioxide gas.

Answer:

iron(lll)oxide

Explanation:

has three oxygen atoms

The correct formula for the compound is iron(III) oxide with two iron atoms and three oxygen atoms. Therefore, option (3) is correct.

Fe₂O₃ is an inorganic compound that has the chemical name Iron(III) oxide. Iron(III) oxide is also known as Hematite or Red iron oxide. This compound is naturally found in rocks of all ages. It is odorless, appears as a Red-brown solid, and has a pH value of 7.

Iron (III) oxide also called ferric oxide, is formed by the oxidation of iron. This can be prepared by electrolyzing a sodium bicarbonate solution in the laboratory, with an iron anode. The hydrated iron(III) oxide obtained which is dehydrated at around 200 °C.

The oxidation state of iron can be calculated as oxygen has an oxidation number of -2.

2x + 3(-2) = 0

2x = 6

x = +3

Therefore, the chemical formula Fe₂O₃ has the name Iron(III) oxide.

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Answer:

Carbon dioxide into energy

Explanation:

Plants are autotrophs and prepare their own food through the process of photosynthesis. During the process of photosynthesis, plants utilizes, carbon dioxide and water in the presence of sunlight and produce energy and oxygen.

Plants cell during photosynthesis, uses carbon dioxide and transform it into energy in the form of glucose and releases oxygen.

Hence, the correct answer is "Carbon dioxide into energy".

Answer:

It contains chemical potential energy.

Explanation:

Answer:

I'm going to have to go with double displacement. Sue me if I'm wrong.

Explanation:

Synthesis? No. There would have to be one product, not two.

Decomposition? No. There would have to be one reactant, not two.

Single displacement? No. There are two elements/compounds that are switching places.

Double displacement? Highly likely. From the reactants' side to the products' side, nitrate and iodine switch places.

Neutralization? Uh, I don't think so. I can't remember why, though.

Combustion? No. O₂ would have to be one of the reactants.

Lead nitrate + potassium iodide(?) ==> lead iodide(?) + potassium nitrate

The question is incomplete, the complete question is;

Suna passes an electric current through a sample of clear, colorless, and odorless liquid. As the experiment continues, bubbles form, and the volume of liquid decreases. Suna collects samples of two colorless, odorless gases that bubble out of the liquid. One of the gases burns. Neither the original liquid nor the other gas burns. Which is the best explanation of her results? The electric current changed some of the sample to gas even though the sample was not breaking down. Therefore, the original liquid is a compound. The electric current released a gas that was odorless and colorless, like the original sample. Therefore, the original liquid is an element. The sample was broken down by the electric current and formed a new substance that could burn. Therefore, the original liquid is a compound. The sample lost some of its volume, but the gas still had the same chemical makeup as the original sample. Therefore, the original liquid is an element.

Answer:

The sample was broken down by the electric current and formed a new substance that could burn. Therefore, the original liquid is a compound.

Explanation:

When electric current is passed through a compound, the compound may become broken down to release its constituents. We refer to this phenomenon as electrolysis. We can now say that the substance has been 'decomposed' electrolytically.

Since the original sample was decomposed to yield a gas that could burn and one that couldn't burn even though the original sample couldn't burn, then the original sample is a compound.