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kow [346]
4 years ago
6

What sample size (grams) of Na3PO4 (FW 164.00) known to be 50.00% pure should be used to consume exactly 40.00 mL of 0.1000 M HC

l to reach the 2nd end point
Chemistry
1 answer:
Mkey [24]4 years ago
3 0

Answer:

0.109 g.

Explanation:

Equation of the reaction:

Na3PO4 + 3HCl --> 3NaCl + H3PO4

Number of moles of HCl = molar concentration × volume

= 0.1 × 0.04

= 0.004 mol.

By stoichiometry, 1 mole of Na3PO4 neutralises 3 moles of HCl. Therefore, number of moles of Na3PO4 = 0.004/3

= 0.0013 mol

Mass of Na3PO4 = molar mass × number of moles

= 0.0013 × 164

= 0.219 g

Since 50% of Na3PO4 was present in the sample. Let 100 g be the total mass of the substance

= 0.219 × 50 g/100 g

= 0.109 g.

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If 1.00 g of reactant a is mixed with 2.00 g of reactant b, what is the theoretical yield of product d, in grams (g)? the molar
WARRIOR [948]

The chemical reaction is as follows:

a+b\rightarrow d

Mass of reactant a is 1 g and molar mass is 94 g/mol. Converting mass into number of moles as follows:

n=\frac{m}{M}=\frac{1g}{94 g/mol}=0.0106 mol

Now, 1 mole of reactant a gives 1 mole of product d thus, 0.0106 mol of reactant a gives 0.0106 mol of product d.

Molar mass of product d is 125 g/mol, converting number of moles into mass as follows:

m=n×M=0.0106 mol×125 g/mol=1.33 g

Similarly, molar mass of reactant b is 118 g/mol and mass is 2 g, converting mass into number of moles,

n=\frac{m}{M}=\frac{2g}{118 g/mol}=0.017 mol

1 mol of reactant b gives 1 mol of product d thus, 0.017 mol will give 0.017 mol of product d.

Converting number of moles into mass as follows:

m=n×M=0.017 mol×125 g/mol=2.12 g

Here, reactant that produces lesser product is limiting reactant and the amount of product it forms is theoretical yield.

Therefore, theoretical yield is 1.33 g.


6 0
3 years ago
An electron initially in a 4p state decays to a lower energy state. which energy state is forbidden?
kogti [31]

The state of energy that is forbidden is 2p orbital. The correct option is b).

<h3>What is the energy state of electrons?</h3>

The energy state of an electron depends upon the presence of the electron on the orbitals. Lower the energy they will be in the lower orbital. When they get higher energy they move to the higher orbital.

By using the Selection Rules for Electron Transitions

1.) ?l = +/- 1 and

2.) ?m = 0, +/- 1

The conservation of angular momentum is required by these laws. A photon's inherent angular momentum is 1. As 4p is higher than 2p and the electron is lowering its energy. So, it will go down to 2p orbital.

Thus, the correct option is b). 2p orbital.

The question is incomplete. Your full question is given below:

a) 3d

b) 2p

c) 1s

d) 2s

To learn more about the energy state of electrons, refer to the link:

brainly.com/question/4138621

#SPJ4

3 0
1 year ago
How many valence electrons does a helium atom have? what is the formula of the ion formed when potassium achieves noble-gas elec
OlgaM077 [116]

> How many valence electrons does a helium atom have?

The electron configuration of Helium is simply 1s2. We see that its outermost shell is the s shell and it contains 2 electrons, therefore the number of valence electrons is also 2.

 

> What is the formula of the ion formed when potassium achieves noble-gas electron configuration?

Potassium has a electron configuration of [Ar] 4s1. To have an electron configuration of only [Ar] which is a noble gas, the one electron from 4s1 should be removed, hence:

<span>K+</span>

3 0
4 years ago
What is the momentum of a 3 kg bowling ball moving at 3 m/s
kvv77 [185]

Answer:

<h2>9 kg.m/s</h2>

Explanation:

The momentum of an object can be found by using the formula

momentum = mass × velocity

From the question we have

momentum = 3 × 3

We have the final answer as

<h3>9 kg.m/s</h3>

Hope this helps you

8 0
3 years ago
What are the signs of the enthalpy change (ΔH°) and the entropy change (ΔS°) for the condensation of CS2(g)?
VARVARA [1.3K]

Answer:

∆H is negative

∆S is negative

Explanation:

The condensation of CS2 implies a phase change from gaseous state to liquid state. The energy of the gaseous particles is greater than that of the liquid particles hence energy is given out when a substance changes from gaseous state to liquid state hence the process is exothermic and ∆H is negative.

Changing from gaseous state to liquid states leads to a decrease in entropy hence ∆S is negative. Liquid particles are more orderly than particles of a gas.

5 0
4 years ago
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