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4 years ago

Write two-step equations to describe the changes of state that take place when a candle burns.

Chemistry

2 answers:

Aloiza [94]4 years ago

8 0

Answer:

Explanation:

In a burning candle, there are both physical and chemical changes. The melting of the solid wax to form liquid wax and the evaporation of liquid wax to form wax vapour are physical changes. The burning of the wax vapour is a chemical change.

-BARSIC- [3]4 years ago

3 0

Chemical reactions are happening everywhere. Chemical reactions in your body digest food, decay your teeth and much more. Chemical reactions occur in batteries to provide electricity, in the oven when you bake a cake, in your hair when it is bleached or coloured, and in your car when it burns fuel.
Explosions are very fast chemical reactions.

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Part 2 please and explain please

vekshin1

1) 7.15 * 10^6

since the exponent of the scientific notation is positive, move 6 places to the right.

so, 7.15 * 10^6 = 7150000

2) 3.03 * 10^-8

Since the exponent of the scientific notation is negative, move the decimal point 8 places to the left.

so, 3.03 * 10^-8 = 0.0000000303

3) 4.9 * 10^-1

since the exponent of the scientific notation is negative, move 1 decimal place to the left.

so, 4.9 * 10^-1 = 0.49

4) 2.886 * 10^5

since the exponent of the scientific notation is positive, move 5 decimal places to the right.

so, 2.886 * 10^5 = 288600

6 0

3 years ago

A solution was prepared by dissolving 0.800 g of sulfur S8, in 100.0 g of acetic acid, HC2H3O2. Calculate the freezing point and

Romashka [77]

Answer: The freezing point of solution is 16.5°C and the boiling point of solution is 118.2°C

Explanation:

To calculate the molality of solution, we use the equation:

$Molality=\frac{m_{solute}\times 1000}{M_{solute}\times W_{solvent}\text{ in grams}}$

Where,

$m_{solute}$ = Given mass of solute $(S_8)$ = 0.800 g

$M_{solute}$ = Molar mass of solute $(S-8)$ = 256.52 g/mol

$W_{solvent}$ = Mass of solvent (acetic acid) = 100.0 g

Putting values in above equation, we get:

$\text{Molality of solution}=\frac{0.800\times 1000}{256.52\times 100.0}\\\\\text{Molality of solution}=0.0312m$

Calculation for freezing point of solution:

Depression in freezing point is defined as the difference in the freezing point of water and freezing point of solution.

$\Delta T_f=\text{freezing point of acetic acid}-\text{Freezing point of solution}$

To calculate the depression in freezing point, we use the equation:

$\Delta T_f=iK_fm$

or,

$\text{Freezing point of acetic acid}-\text{Freezing point of solution}=iK_fm$

where,

Freezing point of acetic acid = 16.6°C

i = Vant hoff factor = 1 (for non-electrolyte)

$K_f$ = molal freezing point depression constant = 3.59°C/m

m = molality of solution = 0.0312 m

Putting values in above equation, we get:

$16.6^oC-\text{freezing point of solution}=1\times 3.59^oC/m\times 0.0312m\\\\\text{Freezing point of solution}=16.5^oC$

Hence, the freezing point of solution is 16.5°C

Calculation for boiling point of solution:

Elevation in boiling point is defined as the difference in the boiling point of solution and freezing point of pure solution.

The equation used to calculate elevation in boiling point follows:

$\Delta T_b=\text{Boiling point of solution}-\text{Boiling point of acetic acid}$

To calculate the elevation in boiling point, we use the equation:

$\Delta T_b=iK_bm$

or,

$\text{Boiling point of solution}-\text{Boiling point of acetic acid}=iK_fm$

where,

Boiling point of acetic acid = 118.1°C

i = Vant hoff factor = 1 (for non-electrolyte)

$K_f$ = molal boiling point elevation constant = 3.08°C/m

m = molality of solution = 0.0312 m

Putting values in above equation, we get:

$\text{Boiling point of solution}-118.1^oC=1\times 3.08^oC/m\times 0.0312m\\\\\text{Boiling point of solution}=118.2^oC$

Hence, the boiling point of solution is 118.2°C

8 0

3 years ago

14) A wavelength of radiation has a frequency of 2.10 x 1014 Hz. What is the wavelength of this radiation in nm, and

Evgesh-ka [11]

Answer:

λ = 1.43 x 10³ meters (radio waves)

Explanation:

c = f·λ => λ = c/f

λ = wavelength = ?

f = frequency = 2.10 x 10¹⁴ Hz = 2.10 x 10¹⁴ cycles/sec

c = speed of light (vacuum) = 3.0 x 10⁸m/sec

λ = c/f = 3.0 x 10⁸m/sec / 2.10 x 10¹⁴sec⁻¹ = 1.43 x 10³ meters (radio waves)

3 0

3 years ago

How have safety concerns about chemicals changed over time?

Alex787 [66]

Answer:

C. As scientists have learned more about chemicals, they have become more aware of their dangers

Explanation:

Chemicals are substances with standard compositions, held together by chemical bonds. Chemicals can exist in different phases such as solid, liquid, and gaseous phases. Over time, with a growing understanding of chemicals, their composition, and their reaction methods, scientists now have a better knowledge of the dangers chemicals can pose. To that effect, they have created standard safety measures for those who have to work with these chemicals.

When these guidelines are strictly adhered to, the chances of suffering accidents, burns, and explosions with these chemicals are significantly reduced.

8 0

3 years ago

Sample Response: The change in her position (from beginning to end), along with the direction, is considered her displacement. T

kykrilka [37]

The sample response given in the question is right.

To find the answer, we need to know more about the distance and displacement.

<h3>How distance differ from displacement?</h3>

Displacement is the shortest distance between the initial and final points of a body.
It is the change in position with a fixed direction.
Displacement is a vector quantity and can be positive, negative or zero values.
Distance is the length of actual path of the body between initial and final positions.
It's a scalar quantity and it can be positive or zero.
The magnitude of displacement is less than or equal to the distance travelled.

Thus, we can conclude that the given sample response is right.

Learn more about distance here:

brainly.com/question/28124225

#SPJ1

3 0

2 years ago