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3 years ago

The group number for alkali metals

Chemistry

1 answer:

kirill115 [55]3 years ago

6 0

The alkali metals include: lithium, sodium, potassium, rubidium, cesium, and francium.

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A gas occupies 18.5L at stp. what volume will it occupy at 735 torr and 57°c?

olga nikolaevna [1]

The volume that will be occupied at 735 torr and 57 c is 23.12 L

calculation

At STP temperature=273 k and pressure=760 torr

by use of combined gas formula

that is P1V1/T1= P2V2/T2

where; P1 =760 torr

T1= 273 K

V1= 18.5 L

P2= 735 torr

T2= 57+273= 330 K

V2=?

by making V2 the formula of subject

V2= T2P1V1/P2T1

V2= [(18.5L x 330 k x 760 torr)/(735 torr x 273 k)]= 23.12 L

5 0

3 years ago

The atomic number of Re is 75. The atomic mass of one of its isotopes is 186. How many neutrons are in an atom of this isotope?

USPshnik [31]

Answer:

B.111

Explanation:

Atomic mass = number of protons(or atomic number) + number of neutrons

186 = 75 + number of neutrons

number of neutrons = 186 -75 = 111

7 0

3 years ago

Aspirin can be prepared from salicylic acid ( C 7 H 6 O 3 CX7HX6OX3), which has a molar mass of 138.12 g/mol, and acetic anhydri

pychu [463]

Answer: The theoretical yield of aspirin is 4.14 g

Explanation:

To calculate the moles :

$\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}$ $\text{Moles of salicylic acid}=\frac{3.20g}{138.12g/mol}=0.023moles$

mass of acetic anhydride = $density\times volume =1.082g/ml\times 3.71ml=4.01g$

$\text{Moles of acetic anhydride}=\frac{4.01g}{102.04g/mol}=0.039moles$

$C_9H_6O_3+C_4H_6O_3\rightarrow C_9H_8O_4+C_2H_3O_2$

According to stoichiometry :

1 mole of salycylic acid require 1 mole of acetic anhydride

Thus 0.023 moles of salycylic acid require= $\frac{1}{1}\times 0.023=0.023moles$ of acetic anhydride

Thus salycylic acid is the limiting reagent as it limits the formation of product and acetic anhydride is the excess reagent.

As 1 mole of salycylic give = 1 mole of aspirin

Thus 0.023 moles of salycylic acid give = $\frac{1}{1}\times 0.023=0.023moles$ of aspirin

Mass of aspirin = $moles\times {\text {Molar mass}}=0.023moles\times 180.15g/mol=4.14g$

Thus theoretical yield of aspirin is 4.14 g

4 0

3 years ago

What is the bond energy required to break one mole of carbon-carbon bonds

ArbitrLikvidat [17]

Answer:

<h2>100 kcal of bond energy</h2>

8 0

3 years ago

Calculate the theoretical yield of ammonia produced by the reaction of 100g of H2 gas and 200g of N2 gas

ipn [44]

To get the theoretical yield of ammonia NH3:
first, we should have the balanced equation of the reaction:
3H2(g) + N2(g) → 2NH3(g)
Second, we start to convert mass to moles
moles of N2 = N2 mass / N2 molar mass
= 200 / 28 = 7.14 moles
third, we start to compare the molar ratio from the balanced equation between N2 & NH3 we will find that N2: NH3 = 1:2 so when we use every mole of N2 we will get 2 times of that mole of NH3 so,
moles of NH3 = 7.14 * 2 = 14.28 moles
finally, we convert the moles of NH3 to mass again to get the mass of ammonia:
mass of NH3 = no.moles * molar mass of ammonia
= 14.28 * 17 = 242.76 g

6 0

3 years ago