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4 years ago

Which of the following is a physical change?

2 answers:

6 0

Hello,
A physical change describes a change that does physically and does not display “chemical” signs which are signs that indicate a precipitate being formed, change in color, density, or producing gas, etc. “Tearing a piece of paper in half” is a physical change because like I said earlier it doesn’t show any chemical change signs. I hope this helps you out!

OLga [1]4 years ago

6 0

Answer:

Tearing a piece of paper in half is a physical change.

Explanation:

A physical change is a change in which the molecular composition of the subject does not change. Since tearing a paper in half does not cause a change in the molecules of the paper, it is a physical change.

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Predict the products of the following reaction and balance the equation: ___Na2CO3(aq) + ___HCl (aq) ->

zheka24 [161]

Answer:

RxN: Na₂CO₃ (aq) + 2HCl (aq) → 2NaCl (aq) + H₂CO₃ (aq)

NIE: n/a

Explanation:

Step 1: Predict (Double Replacement)

Na₂CO₃ (aq) + HCl (aq) → NaCl (aq) + H₂CO₃ (aq)

Step 2: Balance

Na₂CO₃ (aq) + 2HCl (aq) → 2NaCl (aq) + H₂CO₃ (aq)

Step 3: Write Total Ionic Equation

2Na⁺ (aq) + CO₃²⁻ (aq) + 2H⁺ (aq) + 2Cl⁻ (aq) → 2Na⁺ (aq) + 2Cl⁻ (aq) + 2H⁺ (aq) + CO₃²⁻ (aq)

Step 4: Remove Spectator Ions

- Na⁺

- CO₃²⁻

- H⁺

- Cl⁻

Step 5: Write Net Ionic Equation

None.

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3 years ago

How do you think the invention of the microscope influenced the cell theory?

ikadub [295]

Since cells are hard to see the microscope helped them see. scientist were able to actually see cells in tissues placed under the microscope.

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3 years ago

URGENT!! This is timed, PLEASE HELP!

Andrews [41]

Answer:

99.24 gm of nitrogen .

Explanation:

molecular weight of ammonia = 17 , molecular weight of nitrogen = 28.

2 NH₃(g) + 3 CuO(s) → 1N₂(g) + 3 Cu(s) + 3 H₂O(g)

2 x 17 gm 28 gm

( 34 gm )

34 gm of ammonia forms 28 gms of nitrogen

1 gm of ammonia forms 28 / 34 gms of nitrogen

120.51 gn of ammonia forms 28 x 120.51 / 34 gms of nitrogen

28 x 120.51 / 34 gms

= 99.24 gms of nitrogen will be formed .

8 0

4 years ago

Which two factors are used to calculate the kinetic energy of an object?

muminat

Answer:

Mass and Velocity

Explanation:

hope this is the right answer might wrong tho

3 0

3 years ago

Read 2 more answers

Write the net ionic equation (including phases) that corresponds to fe(clo4)2(aq)+na2co3(aq)

olganol [36]

<h2>The net ionic equation that correspond to Fe(ClO4)2 +Na2CO3 is</h2>

<h3>Explanation</h3><h3 /><h3>write the balance chemical equation</h3>

Fe(ClO4)2 (aq) + Na2CO3(aq)→ FeCO3 (s) + 2 NaClO4

<h3>write the ionic equation</h3>

Fe^2+(aq) + 2ClO4 ^-(aq) + 2Na^+(aq) +CO3^2- (aq) → FeCO3 (s) + 2Na^+ + 2ClO4^-

<h3>cancel the spectator ions in both side</h3>

that is ( 2ClO4^- and 2Na+)

the ionic equation is therefore

8 0

3 years ago