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2 years ago

Please help. Just one question

Chemistry

1 answer:

vagabundo [1.1K]2 years ago

4 0

Well, something that I noticed is that the left side is equal to the right side meaning that the sum of the right side is equal to the sun of the left side.

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Do step 3 as outlined in the lab guide. Record your results in the appropriate blanks.

PolarNik [594]

Explanation:

Do the step 3 as outlined in the lab guide. record your results in the appropriate blank.

8 0

3 years ago

What happens to the mass of substances during a physical change?

Anna [14]

Here are the answers in order:

1. During a physical change the substance changes physically.

2. The law of conservation of mass is a law stating the conservation of mass cannot be higher than 46mg or lower than 32mg.

3. A hypothesis is a guess that you make before completing a science experiment, it can be considered a law because it is important to know why you are making the guess.

4. During a chemical change the mass is changing colors. This is a representation of a chemical change.

5. Oil is a non-renewable resource, so it cannot demonstrate the conservation of mass.

6. When the color of the substance has changed or when it explodes.

7. Reactants are the objects that react when in a chemical change.

8. If you follow the rule of not going higher than 46mg and not lower than 32mg then it will automatically follow this law.

Chemical Reactions Part One Video:

1. mass

2. erupt-ant

3. reactant

4. object

5. mixtures

6. molecules

7. color changed

Questions again:

1. A chemical reaction

2. A physical change

3. Because if it is no higher than 46mg and no lower than 32mg then it will follow on it's own.

8 0

3 years ago

Read 2 more answers

Solid aluminum (AI) and oxygen (O_2) gas react to form solid aluminum oxide (Al_2O_3). Suppose you have 7.0 mol of Al and 9.0 mo

Nimfa-mama [501]

Answer:

There will be formed 3.5 moles of Al2O3 ( 356.9 grams)

Explanation:

Step 1: Data given

Numbers of Al = 7.0 mol

Numbers of mol O2 = O2

Molar mass of Al = 26.98 g/mol

Molar mass of O2 = 32 g/mol

Step 2: The balanced equation

4Al(s) + 3O2(g) → 2Al2O3(s)

Step 3: Calculate limiting reactant

For 4 moles Al we need 3 moles O2 to produce 2 moles Al2O3

Al is the limiting reactant, it will be consumed completely (7 moles).

O2 is in excess. There will react 3/4 * 7 = 5.25 moles

There will remain 9-5.25 = 3.75 moles

Step 4: Calculate moles Al2O3

For 4 moles Al we'll have 2moles Al2O3

For 7.0 moles of Al we'll have 3.5 moles of Al2O3 produced

Step 5: Calculate mass of Al2O3

Mass Al2O3 = moles Al2O3 * molar mass Al2O3

Mass Al2O3 = 3.5 moles* 101.96 g/mol

Mass Al2O3 = 356.9 grams

There will be formed 3.5 moles of Al2O3 ( 356.9 grams)

3 0

3 years ago

3. What is the energy of a photon whose frequency is 5.2 x 1015 Hz? Use the equation: E = hxv

anzhelika [568]

Answer:

3. 3.45×10¯¹⁸ J.

4. 1.25×10¹⁵ Hz.

Explanation:

3. Determination of the energy of the photon.

Frequency (v) = 5.2×10¹⁵ Hz

Planck's constant (h) = 6.626×10¯³⁴ Js

Energy (E) =?

The energy of the photon can be obtained by using the following formula:

E = hv

E = 6.626×10¯³⁴ × 5.2×10¹⁵

E = 3.45×10¯¹⁸ J

Thus, the energy of the photon is 3.45×10¯¹⁸ J

4. Determination of the frequency of the radiation.

Wavelength (λ) = 2.4×10¯⁵ cm

Velocity (c) = 3×10⁸ m/s

Frequency (v) =?

Next, we shall convert 2.4×10¯⁵ cm to metre (m). This can be obtained as follow:

100 cm = 1 m

Therefore,

2.4×10¯⁵ cm = 2.4×10¯⁵ cm × 1 m /100 cm

2.4×10¯⁵ cm = 2.4×10¯⁷ m

Thus, 2.4×10¯⁵ cm is equivalent to 2.4×10¯⁷ m

Finally, we shall determine the frequency of the radiation by using the following formula as illustrated below:

Wavelength (λ) = 2.4×10¯⁷ m

Velocity (c) = 3×10⁸ m/s

Frequency (v) =?

v = c / λ

v = 3×10⁸ / 2.4×10¯⁷

v = 1.25×10¹⁵ Hz

Thus, the frequency of the radiation is 1.25×10¹⁵ Hz.

8 0

2 years ago

According to VSEPR theory, a molecule with the general formula AX2E2 (A is the central atom, X is the bonded atom and E is a lon

ratelena [41]

Answer:

see explanation

Explanation:

An AX₂E₂ geometry is derived from an AX₄ parent geometry and is based upon 4 regions of electron density about the central element and defines a tetrahedral geometry and the geometry is bent angular.

An example is the water molecule (H₂O) with two covalent O - H bonds and two free pair electrons on the central oxygen element.

4 0

2 years ago