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3 years ago

How many moles are in 15 grams of calcium

2 answers:

5 0

Atomic mass Ca = 40.0 u.m.a

1 mole Ca ------------- 40.0
? moles Ca ---------- 15 g

15 x 1 / 40 = 0.375 moles of Ca

chubhunter [2.5K]3 years ago

3 0

Approximately 0.374 moles

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To explain the photoelectric effect, Albert Einstein linked the photoelectric effect to an idea from which scientist?

blondinia [14]

Based upon Max Planck's theory of black-body radiation, Einstein theorized that the energy in each quantum of light was equal to the frequency multiplied by a constant, later called Planck's constant. A photon above a threshold frequency has the required energy to eject a single electron, creating the observed effect.

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2 years ago

Read 2 more answers

What is the final volume of a gas (in liters) when the initial volume is 14.00 L at

8_murik_8 [283]

Answer:

$V_2=1344L$

Explanation:

Hello there!

In this case, since we have a problem about volume-pressure relationship, the idea here is to use the Boyle's law to calculate the final volume as shown below:

$P_2V_2=P_1V_1\\\\V_2=\frac{P_2V_2}{P_1}\\$

Then, we plug in the initial and final pressures and the initial volume to obtain:

$V_2=\frac{14.00L*0.9600atm}{0.01000atm}\\\\V_2=1344L$

Regards!

4 0

2 years ago

This equation is not balanced. Click on the coefficient we should change first. help ASAP

horrorfan [7]

Answer: The coefficient we should change first is for $NO_{3}$ .

Explanation:

The given reaction equation is as follows.

$Al + Ni(NO_{3})_{2} \rightarrow Al(NO_{3})_{3} + Ni$

Here, number of atoms present on reactant side are as follows.

Al = 1
Ni = 1
$NO_{3}$ = 2

Number of atoms present on the product side are as follows.

Al = 1
Ni = 1
$NO_{3}$ = 3

To balance this equation, multiply Al by 2 and $NO_{3}$ by 3 on reactant side. Also, multiply $Al(NO_{3})_{3}$ by 2 and Ni by 3 on the product side.

Hence, the equation can be rewritten as follows.

$2Al + 3Ni(NO_{3})_{2} \rightarrow 2Al(NO_{3})_{3} + 3Ni$

Now, number of atoms present on reactant side are as follows.

Al = 2
Ni = 3
$NO_{3}$ = 6

Number of atoms present on product side are as follows.

Al = 2
Ni = 3
$NO_{3}$ = 6

Since, the atoms on both reactant and product side are same. Hence, it is now a balanced chemical equation.

Thus, we can conclude that the coefficient we should change first is for $NO_{3}$ .

7 0

3 years ago

is it possible to convert a saturated salt solution into supersaturated solution,, how?? i want help asap. please

Sliva [168]

Answer:

A saturated solution can become supersaturated when it is cooled. The solubility of solid solutes in liquid solvents increases as the solvent is warmed up. For example, you can dissolve more sugar in warm water as opposed to cold water

I want brainliest plz

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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