How many protons and neutrons are there in an atom of boron11?

Why do the densities of most substances increase when temperature decreases?

vlada-n [284]

This is because temperatures determine the kinetic energy of molecules of a substance, At lower temperatures the molecules have low kinetic energy hence the distance between molecules is not as large as when the kinetic energy is higher (because the molecules bombard less and with less kinetic energy). This means the substance can pack more molecules per volume at lower temperatures. The more the molecules per volume the higher the density.

6 0

3 years ago

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What is Loschmidt’s number? How is it related to Avogadro’s number?

xxMikexx [17]

Loschmidt's constant is referred to as Avogadro's number (they are the same). Their values are 6.02 times 10 to the -34 power.

4 0

3 years ago

What is the half-life of sodium-24? EXPLAIN how you determined your answer.

liraira [26]

Half-life is basically how long it takes for a radioactive molecule to get to 1/2 of its original mass.

so if sodium 24 mass was 5g and it's half life was 24years then:

after every 24years 1/2 of 5g would have decayed. so in 48years there will only be 2.5g left.

8 0

3 years ago

How do I write the formula for binary compounds

Ipatiy [6.2K]

Answer:

101010110101010101010101010101 ;)

Explanation:

3 0

3 years ago

In a laboratory demonstration, a balloon filled with methane and oxygen was exposed to a flame. The result was a brief, large fl

Savatey [412]

Answer:

The equation is not correct:

[CH4 + O2 → CO2 + 2H2O]

Explanation:

The chemical formulas for methane, oxygen, and carbon dioxide are correct, but the equation is not balanced, so we really don't know idf the overall reaction is written correctly.

Let's balance the reaction:

CH4 + O2 → CO2

We need to have the same numbers of atoms on both sides.

Count the numbers of each atom:

Element Reactants Products Difference

C 1 1 0 Balanced

H 4 0 -4 XXX!!!!

O 2 2 0 Balanced

The hydrogens aren't showing up in the products. In fact, there is a product missing entirely from the reaction, H2O, water. The basic reaction is:

CH4 + O2 → CO2 + H2O

Now balance this reaction:

Element Reactants Products Difference

C 1 1 0 Balanced

H 4 2 -2 Hmmmm . . .

O 2 3 1 Uh = oh . . .

This reaction is not possible - there are either too many or too few element atoms (the "Difference").

We can adjust the coefficients for each of the molecules to balanced the equation. This is a bit tricky, but it consists of trying some coefficients that would make things balance. Only whole number coefficients are allowed in the final answer, although fractions might be used in the process to help find the whole numbers.

We need 2 H2O molecules to account for the 4 hydrogens on a single methane molecule

Step 1: CH4 + O2 → CO2 + 2H2O

That leads to:

Element Reactants Products Difference

C 1 1 0 Balanced

H 4 4 0 Balanced

O 2 4 2 Darn

We need more oxygen atoms, so:

Step 2: CH4 + 2O2 → CO2 + 2H2O

This leads to:

Element Reactants Products Difference

C 1 1 0 Balanced

H 4 4 0 Balanced

O 4 4 0 Balanced

This is a balanced reaction, and the correct chemical equation.

3 0

2 years ago