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4 years ago

I need this as soon as possible it’s a test:(

Chemistry

1 answer:

iVinArrow [24]4 years ago

7 0

Answer : The correct match is:

(1) → (k)

(2) → (j)

(3) → (f)

(4) → (d)

(5) → (e)

(6) → (g)

(7) → (a)

(8) → (i)

(9) → (l)

(10) → (c)

(11) → (b)

(12) → (h)

Explanation :

Physical property : It is defined as a change in which the identity of substance does not change.

Physical change : It is defined as something observed while keeping the identity of the substance the same.

Homogeneous mixture : It is defined as something made up of at least two different substances and is usually very difficult to separate. Even distribution of particles.

Heterogeneous mixture : It is defined as something made up of at least two different substances and easily separated by physical means. Unequal distribution of particles.

Chemical property : It is defined as something observed by changing the identity of a substance.

Compound : It is defined as a pure substance made up of at leat two different elements.

Matter : It is defined as anything that has matter and takes up space.

Chemical change : it s defined as a change that creates a new substance or compound.

Extensive property : It is defined as a property that change with the amount of matter present.

Mass : It is defined as the amount of matter contained in an object.

Volume : It is defined as the amount of space a substance takes up.

Intensive property : It is defined as a property that does not change with the amount of matter present.

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A 0.105 L sample of an unknown HNO 3 solution required 35.7 mL of 0.250 M Ba ( OH ) 2 for complete neutralization. What is the c

oksano4ka [1.4K]

Answer: 0.17M

Explanation:

The equation for the reaction is :

2HNO3 + Ba(OH)2 —> Ba(NO3)2 + 2H2O

From the balanced equation, we obtain :

nA = mole of acid = 2

nB = mole of the base = 1

From the question, we obtain:

Va = Vol. Of acid = 0.105L

Ma = conc. Of acid =?

Vb = Vol of base = 35.7 mL = 0.0357L

Mb = conc. of base = 0.25M.

We solve for the conc. of the acid using:

MaVa / Mb Vb = nA / nB

(Ma x 0.105) / (0.25x0.0357) = 2

Cross multiply to express in linear form. We have:

Ma x 0.105 = 0.25 x 0.0357 x 2

Divide both side by 0.105. We have

Ma = (0.25 x 0.0357 x 2) / 0.105

Ma = 0.17M

Therefore the concentration of the acid(HNO3) is 0.17M

3 0

3 years ago

Why do electrons transition between energy levels within the atom, and how do we detect these transitions?

Sedaia [141]

Answer:

See explanation

Explanation:

Electrons transition between energy levels in an atom due to gain or loss of energy. An electron may gain energy and move from its ground state to one of the accessible excited states. The electron quickly returns to ground state, emitting the energy previously absorbed as a photon of light. The wavelength of light emitted is measured using powerful spectrometers.

Atoms can be excited thermally or by irradiation with light of appropriate frequency.

7 0

3 years ago

How many moles of sodium carbonate are contained by 57.3g of sodium carbonate

Lady_Fox [76]

Answer:

$\boxed {\boxed {\sf 0.541 \ mol \ Na_2CO_3}}$

Explanation:

We are asked to find how many moles of sodium carbonate are in 57.3 grams of the substance.

Carbonate is CO₃ and has an oxidation number of -2. Sodium is Na and has an oxidation number of +1. There must be 2 moles of sodium so the charge of the sodium balances the charge of the carbonate. The formula is Na₂CO₃.

We will convert grams to moles using the molar mass or the mass of 1 mole of a substance. They are found on the Periodic Table as the atomic masses, but the units are grams per mole instead of atomic mass units. Look up the molar masses of the individual elements.

Na: 22.9897693 g/mol
C: 12.011 g/mol
O: 15.999 g/mol

Remember the formula contains subscripts. There are multiple moles of some elements in 1 mole of the compound. We multiply the element's molar mass by the subscript after it, then add everything together.

Na₂ = 22.9897693 * 2= 45.9795386 g/mol
O₃ = 15.999 * 3= 47.997 g/mol
Na₂CO₃= 45.9795386 + 12.011 + 47.997 =105.9875386 g/mol

We will convert using dimensional analysis. Set up a ratio using the molar mass.

$\frac {105.9875386 \ g \ Na_2CO_3}{1 \ mol \ Na_2CO_3}$

We are converting 57.3 grams to moles, so we multiply by this value.

$57.3 \ g \ Na_2CO_3} *\frac {105.9875386 \ g \ Na_2CO_3}{1 \ mol \ Na_2CO_3}$

Flip the ratio so the units of grams of sodium carbonate cancel.

$57.3 \ g \ Na_2CO_3} *\frac {1 \ mol \ Na_2CO_3}{105.9875386 \ g \ Na_2CO_3}$

$57.3 } *\frac {1 \ mol \ Na_2CO_3}{105.9875386 }$

$\frac {57.3 }{105.9875386 } \ mol \ Na_2CO_3$

$0.5406295944 \ mol \ Na_2CO_3$

The original measurement of moles has 3 significant figures, so our answer must have the same. For the number we found that is the thousandth place. The 6 in the ten-thousandth place to the right tells us to round the 0 up to a 1.

$0.541 \ mol \ Na_2CO_3$

There are approximately <u>0.541 moles of sodium carbonate</u> in 57.3 grams.

6 0

3 years ago

The name of an oxyacid has the suffix -ous acid. What is the suffix of the oxyanion?

Dima020 [189]

Answer:

-ate

Explanation:

6 0

3 years ago

Hello can anyone help?

e-lub [12.9K]

Answer:

A ) 1, 2 and 3

Explanation:

1 ) is correct because,

K donates 1 electron

F gain 1 electron from K.

If donating and gaining of electrons takes place between two electron, then type of compound formed is ionic.

2 ) is correct because,

K + F -----> KF

3 ) is correct because,

KF is soluble in cold water; very soluble in hot water.

8 0

3 years ago

Read 2 more answers