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Leto [7]
3 years ago
5

Please i need the answer for 18,19,20Answer and I will give you brainiliest ​

Chemistry
1 answer:
dezoksy [38]3 years ago
8 0
Number 18 is correct, number 19 is the particles speed up and the substance expands, and number 20 is decrease in volume
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Aspirin (C9H8O4) is synthesized by reacting salicylic acid (C7H6O3) with acetic anhydride (C4H6O3). The balanced equation isC7H6
prisoha [69]

<u>Answer:</u>

<u>For a:</u> The mass of acetic anhydride needed is 73.91 grams.

<u>For b:</u> The theoretical yield of aspirin is 130.43 grams.

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}   .....(1)

  • <u>For a:</u>

Given mass of salicylic acid = 1.00\times 10^2g=100g

Molar mass of salicylic acid = 138.121 g/mol

Putting values in equation 1, we get:

\text{Moles of salicylic acid}=\frac{100g}{138.121g/mol}=0.724mol

For the given chemical reaction:

C_7H_6O_3+C_4H_6O_3\rightarrow C_9H_8O_4+CH_3COOH

By stoichiometry of the reaction:

1 mole of salicylic acid reacts with 1 mole of acetic anhydride.

So, 0.724 moles of salicylic acid will react with = \frac{1}{1}\times 0.724=0.724mol of acetic anhydride.

Now, to calculate the mass of acetic anhydride, we use equation 1:

Moles of acetic anhydride = 0.724 moles

Molar mass of acetic anhydride = 102.09 g/mol

Putting values in equation 1, we get:

0.724mol=\frac{\text{Mass of acetic anhydride}}{102.09g/mol}\\\\\text{Mass of acetic anhydride}=73.91g

Hence, the mass of acetic anhydride needed is 73.91 grams.

  • <u>For b:</u>

By stoichiometry of the reaction:

1 mole of salicylic acid is producing 1 mole of aspirin.

So, 0.724 moles of salicylic acid will produce = \frac{1}{1}\times 0.724=0.724mol of aspirin.

Now, to calculate the mass of aspirin, we use equation 1:

Moles of aspirin = 0.724 moles

Molar mass of aspirin = 180.158 g/mol

Putting values in equation 1, we get:

0.724mol=\frac{\text{Mass of aspirin}}{180.158g/mol}\\\\\text{Mass of aspirin}=130.43g

Hence, the theoretical yield of aspirin is 130.43 grams.

4 0
3 years ago
What is the name of the phase where stars live out most of their lives?
lisov135 [29]
The correct option is B. 
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1. Pro stars and pre-main sequence star
2. Main sequence  and giant star
3. Variable stars
Major stages in the life of a star can last for millions of years.

8 0
4 years ago
In which location would you expect to find the greatest species diversity?!
Crank
I believe the answer is Canada!
5 0
4 years ago
A 25.0g sample of brass, which has a specific heat capacity of 0.375·J·g−1°C−1, is dropped into an insulated container containin
Angelina_Jolie [31]

Answer:

The equilibrium temperature of water is 25.6 °C

Explanation:

Step 1: Data given

Mass of the sample of brass = 25.0 grams

The specific heat capacity = 0.375 J/g°C

Mass of water = 250.0 grams

Temperature of water = 25.0 °C

The initial temperature of the brass is 96.7°C

Step 2: Calculate the equilibrium temperature

Heat lost = heat gained

Q(sample) = -Q(water)

Q = m*C* ΔT

m(sample)*c(sample)*ΔT(sample) = - m(water)*c(water)*ΔT(water)

⇒m(sample) = the mass of the sample of brass = 25.0 grams

⇒with c(sample) =The specific heat capacity = 0.375 J/g°C  

⇒with ΔT = the change of temperature = T2 - T1 =T2 - 96.7 °C

⇒with m(water) = the mass of the water = 250.0 grams

⇒with c(water) = the specific heat capacity = 4.184 J/g°C

⇒with ΔT(water) = the change of temperature of water = T2 - T1 = T2 - 25.0°C

25.0 * 0.375 * (T2 - 96.7) = - 250.0 * 4.184 J/g°C * (T2 - 25.0°C)

9.375T2 - 906.56 = -1046T2 + 26150

9.375T2 + 1046T2 = 26150 + 906.56

1055.375T2 = 27056.26

T2 = 25.6 °C

The equilibrium temperature of water is 25.6 °C

4 0
3 years ago
Consider the balanced equation below. 4NH3 + 3O2 --&gt; 2N2 + 6H2O What is the mole ratio of NH3 to N2?
AURORKA [14]
The balanced equation given is:
4NH3 + 3O2 .....> 2N2 + 6H2O

From this equation, we can note that 4 moles of NH3 are required to produce 2 moles of N2.

Therefore, the mole ratio of NH3 to N2 is 4:2 which can be simplified into 2:1
4 0
3 years ago
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