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3 years ago

Which of the following could be classified as producing a physical change?

2 answers:

3 0

A physical change involves a change in physical properties. Examples of physical properties include melting, transition to a gas, change of strength, change of durability, changes to crystal form, textural change, shape, size, color, volume and density.

adoni [48]3 years ago

3 0

Physical changes alter only the size, shape, form or matter state of a material. Water boiling, melting ice, tearing paper, freezing water and crushing a can are all examples of physical changes. On the other hand, chemical changes are a bit different. In a chemical change, a new substance is formed.

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Which of the following species is a molecular element?1. neon 2. carbon dioxide3. chlorine 4. sodium 5. none of the above

babymother [125]

Answer:

Explanation:

4 0

4 years ago

2CO2 + 3H2O + 4Br2 C = O = H = Br =

devlian [24]

Explanation:

2CO2 + 3H2O + 4Br2

C = 2

O = 5

H = 6

Br =8

8 0

3 years ago

A large cylindrical tank contains 0.750 m3 of nitrogen gas at 27°C and 7.50 * 103 Pa (absolute pressure). The tank has a tight‐f

Nuetrik [128]

Answer: The answer is 68142.4 Pa

Explanation:

Given that the initial properties of the cylindrical tank are :

Volume V1= 0.750m3

Temperature T1= 27C

Pressure P1 =7.5*10^3 Pa= 7500Pa

Final properties of the tank after decrease in volume and increase in temperature :

Volume V2 =0.480m3

Temperature T2 = 157C

Pressure P2 =?

Applying the gas law equation (Charles and Boyle's laws combined)

P1V1/T1 = P2V2/T2

(7500 * 0.750)/27 =( P2 * 0.480)/157

P2 =(7500 * 0.750* 157) / (0.480 *27)

P2 = 883125/12.96

P2 = 68142.4Pa

Therefore the pressure of the cylindrical tank after decrease in volume and increase in temperature is 68142.4Pa

8 0

3 years ago

A compound has a molecular weight of 146 g/mol. A 0.3250 g sample of the compound contains 0.1605 g of carbon, 0.0220 g of hydro

Sonbull [250]

Answer: The molecular formula is $C_6H_{10}S_2$

Explanation:

We are given:

Mass of $C$ = 0.1605 g

Mass of $H$ = 0.0220 g

mass of $S$ = 0.1425 g

Step 1 : convert given masses into moles.

Moles of C = $\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{0.1605g}{12g/mole}=0.0134moles$

Moles of H = $\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{0.0220g}{1g/mole}=0.0220moles$

Moles of S = $\frac{\text{ given mass of S}}{\text{ molar mass of S}}= \frac{0.1425g}{32g/mole}=0.0044moles$

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C = $\frac{0.0134}{0.0044}=3$

For H = $\frac{0.0220}{0.0044}=5$

For S = $\frac{0.0044}{0.0044}=1$

The ratio of C : H: S= 3: 5: 1

Hence the empirical formula is $C_3H_5S$

The empirical weight of $C_3H_5S$ = 3(12)+5(1)+1(32)= 73g.

The molecular weight = 146 g/mole

Now we have to calculate the molecular formula.

$n=\frac{\text{Molecular weight }}{\text{Equivalent weight}}=\frac{146}{73}=2$

The molecular formula will be= $2\times C_3H_5S=C_6H_{10}S_2$

7 0

3 years ago

How many moles of ammonium nitrate are there in 32.5 mL of a0.125 M NH4NO3 solution?

Nady [450]

Answer: The number of moles of ammonium nitrate is 0.004 moles.

Explanation:

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in mL)}}$

We are given:

Molarity of $NH_4NO_3$ solution = 0.125 M

Volume of solution = 32.5 mL

Putting values in above equation, we get:

$0.125M=\frac{\text{Moles of }NH_4NO_3\times 1000}{32.5mL}\\\\\text{Moles of }NH_4NO_3=0.004mol$

Hence, the number of moles of ammonium nitrate is 0.004 moles.

8 0

4 years ago