All categories

3 years ago

When a andle burns both physical change and chemical change take place how

Chemistry

1 answer:

melamori03 [73]3 years ago

8 0

Answer:

Chemical Changes in Burning Candle: When you light the candle, the wax present near the wick will melt. Wick absorbs the liquid wax. The liquid wax vaporizes due the heat produced by the flame. This wax vapor near to flame burns and gives new substances like Carbon Dioxide, Carbon soot, water vapours, heat and light.

Explanation:

You might be interested in

The function of hydrochloric acid in the gastric juice.

irina [24]

The function of hydrochloric acid is to melt the food

5 0

3 years ago

"When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical

matrenka [14]

Answer: periodic law.

Justification:

1) Although Mendeleev formulated the modern periodic table, ordering the elements according to their physical and chemical properties, there is not such law as Meneleev's Law.

2) The Pauli exclusion principle states that two electrons on an atom cannot have the same 4 quantum numbers, which drives to the fact that only two electrons can stay in the same orbital, each with opposite spin numbers.

3) Hund's rule states that the electrons with the same energy level will occupy the orbitals with the same spin before adding the electrons with the opposite spin.

4) Indeed the periodic law states that the elements are arranged in order of increasing atomic number, and there is a periodic repetition of their physical and chemical properties.

6 0

3 years ago

Read 2 more answers

Calculate the mass of 9.0x10^17 molecules of He gas at STP

Brrunno [24]

$6,02*10^{23} \ \ \ \ \ \rightarrow \ \ \ \ 4g \ He\\
9,0*10^{17} \ \ \ \ \ \ \rightarrow \ \ \ \ m_{x}\\\\
m_{x}=\frac{9*10^{17}*4g}{6,02*10^{23}}\approx5,98*10^{-6}g$

3 0

3 years ago

12. How many moles of atoms are present in 154 g of Na2O?

tia_tia [17]

Answer:

$\boxed {\boxed {\sf A. \ 2.48 \ mol \ Na_2O}}$

Explanation:

We are asked to convert an amount in grams to moles. To do this, we use the molar mass. This is the number of grams in one mole of a substance. It is the same value numerically as the atomic mass on the Periodic Table, however the units are grams per mole, not atomic mass units.

Look up the molar masses for the individual elements.

Sodium (Na): 22.9897693 g/mol
Oxygen (O): 15.999 g/mol

Look back at the formula: Na₂O. Notice there is a subscript of 2 after sodium. This means there are 2 atoms of sodium in every molecule, so we have to multiply sodium's molar mass by 2 before adding oxygen's.

Na₂O: 2(22.9897693 g/mol)+ 15.999 g/mol = 61.9785386 g/mol

Set up a ratio using the molar mass.

$\frac {61.9785386 \ g \ Na_2O}{1 \ mol \ Na_2O}$

Multiply by the given number of grams.

$154 \ g \ Na_2O*\frac {61.9785386 \ g \ Na_2O}{1 \ mol \ Na_2O}$

Flip the ratio so the grams of sodium oxide can cancel each other out.

$154 \ g \ Na_2O*\frac {1 \ mol \ Na_2O}{61.9785386 \ g \ Na_2O}$

$154 *\frac {1 \ mol \ Na_2O}{61.9785386 }$

$\frac {154}{61.9785386 } \ mol \ Na_2O$

$2.48473106141 \ mol \ Na_2O$

The original measurement of grams given has 3 significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place.

2.48473106141

The 4 in the thousandth place tells us to leave the 8.

$2.48 \ mol \ Na_2O$

There are 2.48 moles of sodium oxide in 154 grams, so choice A is correct.

6 0

3 years ago

Sio2(s)+3c(s)→sic(s)+2co(g)

bonufazy [111]

Please explain in more detail

7 0

3 years ago