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Lunna [17]
3 years ago
10

What are three chemical changes and what are three physical changes?

Chemistry
1 answer:
choli [55]3 years ago
8 0

Chemical changes:

burning wood

digesting food

mixing acid and base

Physical changes:

breaking a bottle

melting an ice cube

crumbling a sheet of paper

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It pulls you towards the ground therefore when we jump, or if you drop soemthing, it goes straight back down
6 0
3 years ago
Read 2 more answers
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.

  • 2.48<u>4</u>73106141

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

2.48 \ mol \ Na_2O

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

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4 years ago
What point does the ammonium ions act as a buffer solution? Please this is driving me insane.
Shalnov [3]

Answer:

Explanation:The buffer is a mixture of ammonia (NH3) and ammonium (NH4+). ... Since ammonia (NH3) is a weak base, it will have a pH above 7 and since ammonium (NH4+) is a weak acid, it will have a pH below 7. Ammonia (NH3) is a weak base and ammonium (NH4+) is a weak acid. Ammonia (NH3) is the conjugate base of ammonium (NH4+).

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3 years ago
What is the most likely mode of decay for each?(c) ¹¹⁰₄₁4Ru
zmey [24]

The most likely mode of decay for a neutron-rich nucleus is one that converts a neutron into a proton.

<h3>What is radioactive decay?</h3>

The process through which an unstable atomic nucleus loses energy through radiation is known as radioactive decay, also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration. A substance that has unstable nuclei is regarded as radioactive. Alpha decay, beta decay, and gamma decay are three of the most frequent kinds of decay, and they all entail the emission of one or more particles. Beta decay is a result of the weak force, while the nuclear force and electromagnetism are in charge of the other two mechanisms. The capture of an inner electron from one of the electron shells by an unstable nucleus is the fourth prevalent form of decay.

To learn more about radioactive decay visit:

brainly.com/question/1770619

#SPJ4

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Que materias o asignaturas disciplinarias consideras que están
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Las áreas temáticas que pueden estar involucradas en el cuidado del agua son;

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Química

Geología

oceanografía

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Conservar y compartir es una parte integral de la ciencia ambiental. La ciencia ambiental en sí misma es multidisciplinaria.

Varias áreas temáticas deben estar involucradas en la conservación del medio ambiente.

Estas áreas temáticas incluyen;

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Aprende más: brainly.com/question/10929764

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3 years ago
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