Can u please help me

Answer:

B

Explanation:

Valence electrons only involve in chemical bonding, since they are farthest from the nucleus. Hope this helps!

Answer:

5 g/cm^3

Explanation:

Density of a substance= mass/ volume

Given:

volume = 4,

mass = 20

Assume volume is in cm^3

Mass is in "g"

Then substitute the values

Density of the substance=( 20/4)

= 5 g/cm^3

Answer:

Molecules in both the metal and the surrounding air will start moving at higher speeds.

Explanation:

Temperature is a measure of the average kinetic energy of the molecules in a body. Thus, as the temperature of a body increases, its molecules tend to move faster.

At a high temperature of 150°C, the molecules in the metal hot plate move faster. Similarly, this heat is also transferred to the surrounding air molecules and they too start moving faster.

Therefore at 150°C, molecules in both the metal and the surrounding air will start moving at higher speeds.

Answer:

The space surrounding a magnet within which the magnetic effect is felt is called Magnetic field. A magnetic field is a vector field that describes the magnetic influence of electrical currents and magnetic materials.

Answer:

Explanation:

it is a covalent bond

carbon atom contains 4 electrons in its valance shell.here,carbon atom shares two of its electrons with two electrons of each oxygen atom forming double covalent bond and forms C02 molecule.

Answer:

The process of unstable (or radioactive) atoms becomes stable by emitting radiation. This event over time is called radioactive decay. Alpha decay results in the loss of two protons and two neutrons from the nucleus

Answer:

radioactive disintegration

Explanation:

Answer:

Your answer would be D, Hope this helps.

Answer:

160 g

Explanation:

1 mole of oxygen atom = 16 g

Number of moles of oxygen given = 5 mole

Molecular weight of oxygen molecule = 32 g/ mole

Weight of oxygen in gram = 5 mol x 32 g/mol= 160 g

Therefore, 160 g of oxygen is present in 5 moles.

Answer:

289.8g

Explanation:

Using the formula as follows:

mole = mass/molar mass

Molar mass of SnF = 119 + 19

= 138g/mol

Using mole = mass/molar mass

2.1 = mass/138

mass = 2.1 × 138

mass = 289.8g

Answer:

83.33ml

Explanation:

Firstly, let's notice that 200ml are equal to 0.2L

M=number of moles of the solute ÷ number of liters. Let's call the number of liter by x:

2.5=x÷0.2

x=2.5×0.2

x=0.5

It means you'll need 0.5 mol of HNO. But your solution have 6 moles per liter, so how much do you need? Divide the moles by 12 to have 0.5, so now you need to divide the liter per 12 too. The liter is equal to 1000ml, so:

1000ml÷12=83.33ml

Answer: No it does not

Explanation:

The law of conservation of mass states that mass is neither created nor destroyed and in this equation you start with 1 molecule of Cl and 1 of H, but on the reactants side you end up with 2 of each. To make it follow the law of conservation of mass you would have to balance the equation

Answer:

6.02x10^23

Explanation:

1 mole of water is equivalent to 1 molecule of 6.02x10^23

Answer:

BaF2 + Na2S → BaS2 + 2NaF (balanced equation)

Answer:

Trabalho realizado por máquina térmica  = 250 J

Explanation:

Dado

Eficiência da máquina térmica = 5% = 0,05

A eficiência é igual à proporção do trabalho realizado pela máquina térmica para o calor fornecido a ela

Por isso,

0,05 = Trabalho realizado por máquina térmica / 5000 J

Trabalho realizado por máquina térmica = 5000 J * 0,05 = 250 J

Answer:

Sediment to sedimentary rock (and vice versa) is Compactation and Cementation.

Explanation:

This happens via Lithification, which is the compacting of sediments under pressure.

Answer:

between 5 and 5.5

Explanation:

Answer:

between 5.0 and 5.5

Explanation:

between 5.0 and 5.5

Answer:

chung long

Explanation:

cause 3 plus 2 =9

Answer:

A.

Explanation:

the gradual movement of the continents across the earth's surface through geological time.

Answer:

a

Explanation:

Answer:

[tex]M_{base}=0.0579M[/tex]

Explanation:

Hello there!

In this case, according to the given information in the undergoing chemical reaction, it is possible for us to realize that barium hydroxide reacts with hydrochloric acid in a 1:2 mole ratio, which means that at the equivalence point, we have:

[tex]2n_{base}=n_{acid}[/tex]

That can be written in terms of molarity and volume:

[tex]2M_{base}V_{base}=M_{acid}V_{acid}[/tex]

Thus, we solve for the molarity of the barium hydroxide to obtain:

[tex]M_{base}=\frac{M_{acid}V_{acid}}{2V_{base}} \\\\M_{base}=\frac{0.0895M*32.35 mL}{2*25.00mL}\\\\M_{base}=0.0579M[/tex]

Regards!

Answer:

its false..

Explanation:

pure water is an excellent insulator and does not conduct electricity. The thing is, you won't find any pure water in nature, so don't mix electricity and water.

hope it helps.

Answer:

False

Explanation:

Pure water does not conduct electricity. This is because pure water do not contain any salts. Pure water can conduct electricity when common salt is added to it, as salt solution is conducting in nature.

Answer:

C) 1 x 10-10 M

Explanation:

To solve this question we must use the equation:

Kw = [H+] [OH-]

Where Kw is the equilibrium dissociation of water = 1x10-14

[H+] is the molar concentration of hydronium ion = 1x10-4M

[OH-] is the molar concentration of hydroxyl ion

Replacing:

1x10-14= 1x10-4 [OH-]

[OH-] = 1x10-14 / 1x10-4M

[OH-] = 1x10-10 M

Right option is:

Answer:

have g8igcicg9ccgco

Explanation:

gcohogxzrxog floor. gi gi gi gi. r. uvgi7rz. g yde6ifkg. gg g goog oh g of ifz8fd8dti

Answer:

nnnnaaaoooo. seeeeiiii!!!!!!b k ibhhgj

Explanation:

number of moles = number of particle/ 6.02X10^23

= 12.044 X 10^24/6.02×10^23

=20.0066 moles so round it up to 3 S.F

So

=20.0moles

Answer:

12 mmilligrams of Po-218 was the mass of the original starting material

Explanation:

The half-life of a radioactive material is the time taken for half the amount ofnthe original material present in a radioactive material to decay or disintegrate.

After each half-life, half the original material present at the start remains.

For the radioactive polonium-218 having a half-life of 3.04 minutes, it means that if 1 g is the starting material, after 3.04 minutes, 1/2 g will be remaining; after, 6.08 minutes 1/2 of 1/2 which is 1/4 of the starting material will be remaining; and after 9.12 minutes, 1/2 of 1/4 = 1/8 g will be remaining.

From the question, number of half-lives undergone after 9.12 minutes = 9.12/3.04 = 3 half-lives.

After 3 half-lives, 1/8 of the original material is remaining.

1/8 = 1.50 mg

The original mass of the sample at the start = 1.50 mg × 8 = 12 mg

Therefore, 12 milligrams of Po-218 was the mass of the original starting material.

The question is incomplete, the complete question is;

A pool owner adds a compound containing chlorine to the pool to disinfect it. However, too much of the compound is added. As a result, the water becomes too acidic. What could the pool owner do to reduce the acidity of the pool?

He could add another acid to the pool to compete with the existing acid.

He could add a metal salt to the pool to precipitate the acid.

He could add a base to the pool to neutralize the acid.

Answer:

He could add a base to the pool to neutralize the acid.

Explanation:

The reaction between an acid and a base is called a neutralization reaction. A neutralization reaction is defined as a reaction between an acid and a base leading to the formation of salt and water only.

If the owner of the pool discovers that the pool has become too acidic, all that needs to be done is to introduce a base into the pool that will neutralize the acid according to the reaction;

Acid + base ------> salt + water

Answer:

Aluminium is malleable. It means it can be hammered or changed into other shapes easily. In this case, the shape of a soft drink can.

Explanation:

This is my answer.