What is the difference between atom and it’s ion ?

Is melting sugar a chemical or physical change? Please provide an explanation

liraira [26]

Answer:

Hola Amigo! Here's Ur Answer :D

Explanation:

The chemical reaction we are most familiar with is that of melting: sugar decomposes at a temperature ranging between 184 and 186°C. This is a very recent discovery we owe to a team of researchers in Illinois. Basically, when we heat sucrose gently, this produces a phenomenon known as “ apparent melting ”.

Happy to Help! :D

3 0

2 years ago

Read 2 more answers

Drinking water may contain a low concentration of lead ion (Pb2 ) due to corrosion of old lead pipes. The EPA has determined tha

Lynna [10]

Answer:

3.861x10⁻⁹ mol Pb⁺²

Explanation:

We can <u>define ppm as mg of Pb²⁺ per liter of water</u>.

We<u> calculate the mass of lead ion in 100 mL of water</u>:

100.0 mL ⇒ 100.0 / 1000 = 0.100 L

0.100 L * 0.0080 ppm = 8x10⁻⁴ mg Pb⁺²

Now we <u>convert mass of lead to moles</u>, using its molar mass:

8x10⁻⁴ mg ⇒ 8x10⁻⁴ / 1000 = 8x10⁻⁷ g

8x10⁻⁷ g Pb²⁺ ÷ 207.2 g/mol = 3.861x10⁻⁹ mol Pb⁺²

4 0

2 years ago

What temperature will the water reach when 10.1 g CaO is dropped into a coffee cup containing 157 g H2O at 18.0°C if the followi

Zepler [3.9K]

Answer:

Final temperature attained by water = 34.6°C

Explanation:

The reaction of CaO and H₂O is an <em>exothermic reaction</em>. The equation of reaction is given below:

CaO + H₂O ----> Ca(OH)₂

The quantity of heat given off, ΔH°rxn = 64.8KJ/mol = 64800J/mol

Number of moles of CaO = mass/molar mass, where molar mass of Ca0 = 56g/mol, mass of CaO = 10.1g

Number of moles of CaO = 10.1g/56g/mol =0.179moles

Quantity of heat given off by 0.179 moles = 64800 *0.179 = 11599.2J/mol

Using the formula, <em>Quantity of heat, q = mass * specific heat capacity * temperature rise.</em>

mass of mixture = (10.1 + 157)g = 167.1g, Initial temperature = 18.0°C

Final temperature(T₂) - Initial temperature(T₁) = Temperature rise

11599.2J/mol = 167.1g * 4.18J/g·°C * ( T₂ - 18.0°C)

11599.2 = 698.478T₂ - 12572.604

11599.2 + 12572.604 = 698.478T₂

698.478T₂ = 24171.804

T₂ = 34.6°C

Therefore, final temperature attained by water = 34.6°C

6 0

2 years ago

Acetic acid has a Kb of 2.93 °C/m and a normal boiling point of 118.1 °C. What would be the boiling point of a solution made by

alexdok [17]

Boiling point elevation is given as:

ΔTb=iKbm

Where,

ΔTb=elevation in the boiling point

that is given by expression:

ΔTb=Tb (solution) - Tb (pure solvent)

Here Tb (pure solvent)=118.1 °C

i for CaCO3= 2

Kb=2.93 °C/m

m=Molality of CaCO₃:

Molality of CaCO₃=Number of moles of CaCO₃/ Mass of solvent (Kg)

=(Given Mass of CaCO3/Molar mass of CaCO₃)/ Mass of solvent (Kg)

=(100.0÷100 g/mol)/0.4

= 2.5 m

So now putting value of m, i and Kb in the boiling point elevation equation we get:

ΔTb=iKbm

=2×2.93×2.5

=14.65 °C

boiling point of a solution can be calculated:

ΔTb=Tb (solution) - Tb (pure solvent)

14.65=Tb (solution)-118.1

Tb (solution)=118.1+14.65

=132.75

3 0

2 years ago

A 100-gram sample of material requires 1220 calories of heat energy to raise its temperature from 20 0C to 80 0C. What is the sp

SashulF [63]

Taking into account the definition of calorimetry, sensible heat and latent heat, the specific heat capacity of the material is 0.203 $\frac{calories}{gC}$ .