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3 years ago

Please help!!!

Chemistry

1 answer:

Aloiza [94]3 years ago

4 0

Answer:

3 × 10¯¹⁰

Explanation:

9×10² ÷ 3×10¹²

The above expression can be simplified as follow:

9×10² ÷ 3×10¹²

Recall:

9 = 3²

9×10² ÷ 3×10¹² = 3²×10² ÷ 3×10¹²

Recall:

a^m ÷ a^n = a^(m – n)

3²×10² ÷ 3×10¹² = 3^(2 – 1) × 10^(2 – 12)

= 3¹ × 10¯¹⁰

Recall:

a¹ = a

3¹ × 10¯¹⁰ = 3 × 10¯¹⁰

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44. Convert the following. Express your answers in

professor190 [17]

Answer:

A = 0.75 ×10² KJ.

B = 3.9 ×10³ dg

C = 0.22 × 10² μl.

Explanation:

A = 7.5 ×10⁴ j to kilo joules

7.5 ×10⁴ / 1000 = 0.75 ×10² KJ.

Joule is the smaller unit while kilo joule is the larger unit. One kilo joule equals to the thousand joule that's why we will divide the given value by 1000 in order to convert into KJ.

B = 3.9 ×10⁵ mg to decigrams.

3.9 ×10⁵ / 100 = 3.9 ×10³ dg

Decigram is larger unit while milligram is smaller unit. One decigram is equal to the 100 milligram. In order to convert the given value into decigram we have to divide the value by 100.

C = 2.21 ×10⁻⁴ dL to micorliters

2.21 ×10⁻⁴ ×10⁵ = 0.22 × 10² μl.

Deciliter is bigger unit then micro liter . One deciliter equals to the 100000 micro liters. In order to convert the dL into micro liter we have to multiply the given value with 100000.

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4 years ago

A little boy has placed his pet squirrel into a balloon with a volume of 3L at a pressure of 1.0 atm. If the boy takes his pet s

s2008m [1.1K]

Answer: The squirrel's balloon will be 0.86 L

Explanation:

To calculate the new volume, we use the equation given by Boyle's law. This law states that pressure is directly proportional to the volume of the gas at constant temperature.

The equation given by this law is:

$P_1V_1=P_2V_2$

where,

$P_1\text{ and }V_1$ are initial pressure and volume.

$P_2\text{ and }V_2$ are final pressure and volume.

We are given:

$P_1=1.0atm\\V_1=3L\\P_2=3.5atm\\V_2=?$

Putting values in above equation, we get:

$1.0\times 3L=3.5\times V_2\\\\V_2=0.86$

Thus the squirrel's balloon will be 0.86 L

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3 years ago

Which subatomic particle has negligible mass and travels around outside the nucleus?

allsm [11]

The electron is a subatomic particle that has a negative charge and a negligible mass. The electron travels around out side the nucleus.

The subatomic particles that are inside the nucleus are protons and neutrons.

The answer to your question is electron.

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3 years ago

Read 2 more answers

Select the equations below that represent physical changes.

Ierofanga [76]

Physical changes- any change in the physical properties of the substance is a physical change. Generally physical properties include color, state, size , shape, odour, appearance . In any phyical change, no new substance is formed.

Chemical changes- any change in the chemical properties of the substance is a chemical change. Chemical properties changes only when something new is formed during a reaction.

∴ Part A- 2 H2O(l) → 2 H2(g) + O2(g)

In this, H2 and O2 is produced during the reaction which is different from H20. Thus, it is a chemical change.

Part B- H2O(l) → H2O(s)

In this, only the state of water changes from liquid to solid and no new product is formed. Thus, it is a physical change.

Part C-CO2(s) → CO2(g)

In this also, only the state of CO2 changes from solid to gas and no new product is formed. Thus, it is a physical change.

Part D-H2(g) → 2 H(g)

In this reaction, H2 molecule is dissociated into 2 hydrogen atom leading to formation of new products. Thus, it is a chemical change.

Finally, equations that represent physical changes are - B and C

B. H2O(l) → H2O(s)

C. CO2(s) → CO2(g)

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3 years ago

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