When a 10% hydrochloric acid soultion is heated the test tube should alwayd be pointed?

CaSO4. It has 6 atoms while Fe2O3 has 5 atoms

Explanation:

Fe2O3 contains 2 atoms of Iron(Fe) and 3 atoms of Oxygen(O) = 2 + 3 = 5 atoms

CaSO4 contains 1 atom of Calcium(Ca), 1 atom of Sulphur(S) and 4 atoms of Oxygen(O) = 1 + 1 + 4 = 6 atoms

Answer:

Based on the difference in solubility one can perform the process of purification of the benzoic acid contaminated with sodium chloride. The benzoic acid does not get soluble in cold water, while the sodium chloride is soluble in cold water.  

Thus, for separation, the supplementation of cold water can be done into the mixture in the experiment of purifying benzoic acid from sodium chloride. In the process, the mixture is placed on the ice bath and is stirred well, in the end, the solution is filtered. The filtrate contains sodium chloride and on the filter paper pure benzoic acid is collected.  

Answer:

K.E. = 5.4362 × 10⁻¹⁹ J

Explanation:

The expression for Bohr velocity is:

Applying values for hydrogen atom,  

Z = 1

Mass of the electron () is 9.1093×10⁻³¹ kg

Charge of electron (e) is 1.60217662 × 10⁻¹⁹ C

= 8.854×10⁻¹² C² N⁻¹ m⁻²

h is Plank's constant having value = 6.626×10⁻³⁴ m² kg / s

We get that:

Given, n = 2

So,

Kinetic energy is:

So,

K.E. = 5.4362 × 10⁻¹⁹ J

Isopropyl methyl ether is slightly soluble in water because the oxygen atom of ethers with 3 or lesser carbon atoms can form hydrogen bonds with water. Therefore, the given statement is true.

What is hydrogen bonding?

Hydrogen bonding is a special class of attractive intermolecular forces that arise because of the dipole-dipole interaction between hydrogen that is bonded to a highly electronegative atom and another highly electronegative atom that lies in the neighborhood of the hydrogen atom.

For example, in water, hydrogen is covalently bonded to the oxygen atom. Therefore, hydrogen bonding arises because of the dipole-dipole interactions between the hydrogen atom of one water molecule and the oxygen atom of another water molecule.

The solubility of ether in water depends upon the extent of the formation of hydrogen bonds with water. Ether which contains three carbon atoms is soluble in water due to these lower hydrocarbon atoms can form hydrogen bonding with water.  

But the solubility of hydrocarbons or ethers decreases as increase the number of carbon atoms. This is because higher ethers or ethers with more carbons have more hydrophobic parts. Therefore they cannot be soluble in water as they cannot form hydrogen bonds with water molecules.

Learn more about hydrogen bonding, here:

brainly.com/question/15099999

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Answer:

True

Hydrogen bond is a partial intermolecular bonding interaction between a lone pair on an electron rich donor atom, particularly the second-row elements nitrogen (N), oxygen (O), or fluorine (F), and the antibonding orbital of a bond between hydrogen (H) and a more

electronegative atom or group. Such an interacting system is generally denoted Dn–H···Ac, where the solid line denotes a polar covalent bond, and the dotted or dashed line indicates the hydrogen bond. The use of three centered dots for the hydrogen bond is specifically recommended by the IUPAC. While hydrogen bonding has both covalence and electrostatic contributions, and the degrees to which they contribute are currently debated, the present evidence strongly implies that the primary contribution is covelant.

Hydrogen bonds can be intermolecular (occurring between separate molecules) or

intramolecular (occurring among parts of the same molecule)

Answer:

Explanation:

I need more information to answer this question and a better figure.

1. What is the frequency of the NMR machine?

Possible solution:

1. coupling constant Jab (in ppm) is given by

\nu_{a} - \nu_{b} = 4J_{ab}

2. Jab (in ppm) * Frequency of machine in (MHz)/106 is Jab in Hz

3. for cis vicinal Hydrogen Jab = 6-14 Hz

4. for trans vicinal Hydrogens Jab = 11-18 Hz

Now, considering 2 doublets are centered at 7.14 and 7.28 ppm , it gives

7.14 -7.28 = 4 Jab  

thus, Jab = 0.07 ppm

Now if we consider a 100 MHz machine,

Jab = 7 Hz , thus indicating cis product

but if machine is 300 MHz

then Jab = 21 Hz , thus indicating a trans product.

But, most probably I feel it is a trans product. I hope it helps.

Answer:

1.25 g

Explanation:

Now we have to use the formula;

N/No = (1/2)^t/t1/2

N= mass of cesium-137 left after a time t (the unknown)

No= mass of cesium-137 present at the beginning = 5.0 g

t= time taken for 5.0 g of cesium-137 to decay =60 years

t1/2= half life of cesium-137= 30 years

Substituting values;

N/5= (1/2)^60/30

N/5= (1/2)^2

N/5= 1/4

4N= 5

N= 5/4

N= 1.25 g

Therefore, 1.25 g of cesium-137 will remain after 60 years.