Please help me!!! 12 points :)

Answer:

community

Explanation:

Answer:

The correct answer is population. I took the test and got it right.

Answer:

D.

Explanation:

Because protons and neutrons make up the mass of an atom.

Answer:

In the gold crystal, the atoms are bonded by freely moving electrons. In the salt crystal, the atoms are bonded by the attraction of opposite electrical charges.

Explanation:

A.pex

A crystal of Gold (Au) has metallic bonding whereas a crystal of NaCl has ionic bonding.

Chemical bonding refers to the formation of a chemical bond between two or more atoms, molecules or ions to give rise to a chemical compound.

Ionic bonding occurs by transfer of electrons from one atom to another and is usually between a metal and a non metal atom. This type of bond is classically described as occurring when atoms interact with one another to either lose or gain electrons.

Metallic bonds are the chemical bonds that hold atoms together in metals.

Therefore, A crystal of Gold (Au) has metallic bonding whereas a crystal of NaCl has ionic bonding.

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Answer:

Explanation: The longer the alkyl chain, the less soluble in water is the alcohol. Methanol and ethanol are infinitely miscible in water; propanol and butanol have limited solubility. ... Hydrogen bonding with water thus becomes less viable, and solubility of the long-chain alcohol IN WATER decreases.

Explanation:

We use roman numerals to indicate the oxidation state of metal atoms when naming compounds especially in the case of coordination compounds. It is a standard system of nomenclature.

Oxidation state of a species is the number electrons gained or lost. Oxidation state increases if electrons are lost from the atom and it will be decreased if electrons are gained.

For example, copper is in + 2 oxidation state in CuSO₄, thus it can be indicated as Cu(II). Copper can exists is +3 oxidation too. Thus the representation will be Cu (III).

All the transition metals like copper exhibit various oxidation state. So it is important to indicate in which oxidation state they are in a particular compound. In the compound Fe₂O₃, iron is in + oxidation state whereas in FeSO₄, it can be +2 . Thus it is important to note whether it is Fe (II) or Fe (III).

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Answer: Mutations can cause instant adaptations, while natural selection is the process by which adaptations occurs over a series of generations. Adaptations are changes or processes of changes by which an organism or species becomes better suited for its environment. A mutation is an alteration of the DNA sequence.

Answer:

there will be less and less space

Explanation:

Answer:

It’s false

Explanation:

it could be true if the question mentioned alkaline solution

Answer:

True

Explanation:

Phenolphthalein is colorless in the presence of an acid and turns pink in the presence of a base.

Answer:

Explanation:

4

The mole fraction of sulfuric acid : 0.073

Given

3.75 M sulfuric acid solution that has density of 1.230 g/mL

Required

The mole fraction

Solution

3.75 M = 3.75 mol/L

For 1 L solution :

mass of solution = 1230 g

mass Sulfuric acid : 3.75 mol x 98 g/mol=367.5 g

mass water = 1230-367.5 = 862.5 g

mol water = 862.5 : 18 g/mol= 47.92

mol total = 3.75 + 47.92 = 51.67

mole fraction of sulfuric acid :

= 3.75 : 51.67

= 0.073

Answer:

here you go

Explanation:

5 elements and properties:

Boron- The chemical properties of boron are more similar to carbon and silicon than elements of its own group, although boron is more electron deficient. Boron has a high affinity for oxygen-forming borates, and reacts with water at temperatures above 100 °C to form boric acid and other boron compounds.

Carbon- As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. The most common isotope of carbon has 6 protons and 6 neutrons, and has an atomic mass of 12.0107 amu. Its ground state electron configuration is 1s22s22p2.

Nitrogen-  Nitrogen gas (chemical symbol N) is generally inert, nonmetallic, colorless, odorless and tasteless. Its atomic number is 7, and it has an atomic weight of 14.0067. Nitrogen has a density of 1.251 grams/liter at 0 C and a specific gravity of 0.96737, making it slightly lighter than air.

Oxygen- is the air you breath

Nickel- Nickel is a hard silver white metal, which forms cubic crystals. It is malleable, ductile, and has superior strength and corrosion resistance. The metal is a fair conductor of heat and electricity and exhibits magnetic properties below 345°C

5 compounds and properties:

Water - Formula: H2O = Hydrogen2 + Oxygen. ...

Hydrogen Peroxide - Formula: H2O2 = Hydrogen2 + Oxygen2 ...

Salt - Formula: NaCl = Sodium + Chlorine. ...

Baking Soda - Formula: NaHCO3 = Sodium + Hydrogen + Carbon + Oxygen3

Octane - Formula: C8H18 = Carbon8 + Hydrogen18

hope this helps

Answer: B

Explanation: A fluorine atom has nine protons and nine electrons, so it is electrically neutral. (neutral =0)

The nucleus of a fluorine atom has a charge of zero as the atom has equal number of positive and negative charges.

An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.

The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.

Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.

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Answer:

1.725e+18

Explanation:

Answer: The state of maater for HgBr is solid.

Explanation:

A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.  

A double displacement reaction in which one of the product is formed as a solid is called as precipitation reaction.  

The balanced chemical equation is:

[tex]HgNO_3(aq)+KBr(aq)\rightarrow HgBr(s)+KNO_3(aq)[/tex]

Answer:

Three main parts are Protons (pos charge) Neutrons (no charge) Electrons (negative charge) and the electron is found on the outside of the nucleus

Explanation:

Answer:

Electrons

Explanation:

Answer:

Electrons are not found in the nucleus for they are orbiting the atom.

Answer:

European stability mechanism

Answer:

Explanation:

1 mole of oranges contains 6.02 x1023 oranges. 1 mole of helium gas contains 6.02 x1023 helium atoms. 1 mole of water contains 6.02 x1023 water molecules.

...

Answer:

25194.56

Explanation:

You'll  need a scientifuc calculator

2.91*10^22*1 = 2.91E22

2.91E22-/6.02*10^23=25194.56

6.02*10^22 Is the Mole number

tell me what to do dudette

Answer:

Explanation:

The trick here is to realize that if you know the volume of a gas at STP, you can use the fact that

1

mole of any ideal gas occupies

22.7 L

under STP conditions to calculate how many moles of gas you have in your sample.

Under STP conditions:

1 mole of an ideal gas = 22.7 L

−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

In your case, you know that your sample of gas occupies

2.28 L

under STP conditions, which are currently defined as a pressure of

100 kPa

and a temperature of

0

∘

C

.

This means that your sample will contain

2.28

L

⋅

molar volume of a gas at STP



1 mole gas

22.7

L

=

0.10044 moles gas

Now, the molar mass of the gas is the mass of exactly

1

mole of the gas. In your case, you know that you get

3.78 g

for every

0.10044

moles, which means that you have

1

mole

⋅

3.78 g

0.10044

moles

=

37.6 g

Since this is the mass of

1

mole of gas, you can say that the molar mass of the gas is

molar mass = 37.6 g mol

−

1

−−−−−−−−−−−−−−−−−−−−−−−

Answer:

See explanation

Explanation:

We know that surface area is an important determinant factor in the study of reaction rate. This is the reason why finely divided marble chips react faster than lumps of marble in the reaction between marble chips and dilute HCl.

Now imagine that i have a lump of marble and i have finely divided marble. Then i also have a solution of 0.5 M dilute HCl. If i introduce 1g of the lump  of marble into 250 ml solution of the 0.5 M HCl in one beaker and introduce 1g of finely divided marble into another 250 ml solution of 0.5 M HCl in a separate beaker, we will notice that the finely divided marble chips reacts faster as evidenced by the quicker effervescence of CO2 gas from the later compared to the former.

Hence, smaller marble chips reacts faster with dilute HCl than a lump of marble.

Answer:

yes the above given answer is absolutely correct I agree with u man on the above.

Answer:

19.5g

Explanation:

Given parameters:

Volume of propane gas = 9.95L

Unknown:

Mass of propane gas =  ?

Solution:

To solve this problem, find the number of moles first.

    At STP;

        22.4L of gas makes up 1 mole

         9.95L of gas will have a [tex]\frac{9.95}{22.4}[/tex]    = 0.44mole

So;

   Mass of propane gas  = number of moles x molar mass

Molar mass of propane  = 3(12) + 8(1)  = 44g/mol

    Mass  = 0.44 x 44  = 19.5g

Answer:

Grass

Explanation:

On a hot summers day, while barefoot Concrete normaly has heat absorbed into it. (Or on top) So when you go to Walk on it, It normally burns the heel.

Hope I helped and Have a great day!

brainliest?

Answer:

grass

Explanation:

the concrete has a higher specific heat capacity and is basically hotter than the grass which has a lower one

Answer:

LiOH+CH3COOH=C2H3LiO2+H2O balanced equation

Explanation:

lithium hydroxide-> LiOH

hydrogen acetate->CH3COOH

lithium acetate->C2H3LiO2

water->H2O

LiOH+CH3COOH=C2H3LiO2+H2O

Li=1,O=3,H=5,C=2 --> Li=1,O=3,H=5,C=2

the two sides have same numbers so it is balanced.

Answer:

True

Explanation:

Sometimes you will need to convert from grams to moles, or moles to grams

Answer:

This chemical equation represents a decomposition reaction. This identification is based on the fact that the single reactant chemical compound breaks down into two different chemical substances that are different from the initial chemical substance.

Explanation:

it was the sample response lol

A reactant is broken down into two or more products in the decomposition reaction. The given reaction is a decomposition reaction.

Decomposition reaction:

In this type of chemical reaction, a reactant is broken down into two or more products.

For example- Ammonium nitrate is broken down into nitrous oxide and water molecules.

[tex]\bold {NH_4NO_3 \rightarrow N_2O + 2H_2O}[/tex]

Therefore, the given reaction is a decomposition reaction.

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