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3 years ago

Which energy changes in the enthalpy of solution are endothermic, and which are exothermic?

1 answer:

8 0

When energy is needed in order for the reaction to happen, then that reaction is known as endotermic. When the reaction has as a result energy then it is exotermic. An example of an endotermic reaction would be photosynthesis, for an exotermic: combustion.

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Write the ionization equation for hypochlorous acid, HClO, dissolved in water.

Pavel [41]

Answer:

HClO (l) → H⁺ (aq) + ClO⁻ (aq)

proton and hypochlorite.

Explanation:

HClO (Hypochlorous acid)

This is a weak acid that can be dissociated as this:

HClO (l) → H⁺ (aq) + ClO⁻ (aq)

proton and hypochlorite.

It is a weak acid, so it can adopt a Ka for its equilibrium

HClO + H₂O ⇄ H₃O⁺ + ClO⁻ Ka

Molar mass = 52.46 g/m

5 0

3 years ago

What is the concentration of FeCl3 in a solution prepared by dissolving 10.0 g of FeCl3 in enough water to make 275 mL of soluti

puteri [66]

Answer: The concentartion of solution will be 0.224 M

Explanation:

Molarity : It is defined as the number of moles of solute present per liter of the solution.

Formula used :

$Molarity=\frac{n\times 1000}{V_s}$

where,

n= moles of solute = $\frac{\text{Given mass}}{\text{Molar mass}}=\frac{10.0g}{162.2g/mol}=0.0616moles$

${V_s}$ = volume of solution in ml = 275 ml

Now put all the given values in the formula of molarity, we get

$Molarity=\frac{0.0616\times 1000}{275ml}=0.224mole/L$

Therefore, the concentration of solution will be 0.224 M

7 0

3 years ago

Write the molecular formula of ferric oxide and calcium hydroxide by criss-cross method

irina [24]

<h3>Ferric Oxide:-</h3>

$\setlength{\unitlength}{1cm}\begin{picture}(0,0)\thicklines\put(0,3){\bf Fe}\put(0,0){\bf -3}\put(4,3){\sf O}\put(4,0){\bf -2}\put(0.2,2.9){\vector(4,-3){3.5}}\put(3.8,2.9){\vector(-4,-3){3.5}}\end{picture}$

$\\ \sf\longmapsto Fe_2O_3$

<h3>Calcium Hydroxide:-</h3>

$\setlength{\unitlength}{1cm}\begin{picture}(0,0)\thicklines\put(0,3){\bf Ca}\put(0,0){\bf 2}\put(4,3){\sf OH}\put(4,0){\bf -1}\put(0.2,2.9){\vector(4,-3){3.5}}\put(3.8,2.9){\vector(-4,-3){3.5}}\end{picture}$

$\\ \sf\longmapsto Ca(OH)_2$

4 0

3 years ago

Explain what the terms "Pyranose" and "Furanose" represent

Illusion [34]

Answer:

hhh

Explanation:

Pyranose is collective term for the saccharides which have chemical structure which includes six-membered ring that consists of one oxygen atom and five carbon atoms.

Furanose is collective term for carbohydrates which have chemical structure which includes five-membered ring system that consists of one oxygen atom and four carbon atoms.

Glucose exists both in pyranose and furanose form. It's structure is shown in image.

5 0

3 years ago

What number do you never write as a coefficient?

N76 [4]

Answer:

When no coefficient is written in front of a formula it is assumed to be 1. 4. Numbers appearing in the formulas are known as subscripts. These can never be changed when balancing the equation or you will change the identity of the substance.

Explanation:

1. Reactants go on the left hand side and products go on the right hand side of a chemical equation. Be sure to write the correct formulas for the reactants and products.

· Remember atoms are conserved in a chemical reaction. ie they are neither created or destroyed. So all the atoms in the reactants must end up somewhere among the products.

2. Count the number of atoms of each element, compound or ion in the reactants and products. If they are not equal proceed further.

3. Balance the atoms one at a time by placing coefficients in front of the formula so that the numbers of atoms of each element are equal on both sides of the equation. Remember atoms may exist in an element, compound or ion.

· It is usually easier to start with the atoms that occur in only one substance on each side of the equation.

· Balance the atoms that occur in compounds before attempting to balance atoms that occur in elemental form. e.g. H2, O2 or Cl2

· To make it easier if a polyatomic ion appears unchanged on both sides of the equation treat it as a whole unit.

· When no coefficient is written in front of a formula it is assumed to be 1.

4. Numbers appearing in the formulas are known as subscripts. These can never be changed when balancing the equation or you will change the identity of the substance.

· Remember with subscripts, any number to the right of parentheses multiplies each subscript within the parentheses.

eg Fe2(SO4)3 contains 2 Fe atoms, 3 S atoms and 12 O atoms.

5. Finally make sure that all the coefficients are in the smallest possible whole number ratio.

4 0

3 years ago