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Andre45 [30]
4 years ago
13

Consider the following properties: I) The red color of rubies is due to the presence of chromium ions. II) Objects made of silve

r become tarnished. III) The boiling point of ethanol is 78◦C. Which is/are chemical?
Chemistry
1 answer:
quester [9]4 years ago
5 0

Answer:

II) Objects made of silver become tarnished.

Explanation:

Physical properties are the properties which can be observed without changing identity of substance.

Chemical properties are the properties which describe how the substance changes into the different substance completely.

Boiling is an example of physical change in state of the substance. Color is also an example of physical property like boiling point and hence these are constants. The reason of the color is that the chromium ions shows certain colors as the electrons are excited due to absorption of the light. The tarnishing of the silver is an example of the chemical change which occurs due to the reaction of the silver with oxygen. This is also known as corrosion.

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Which of the following bodily organs or systems can be affected by ionizing radiation?
GrogVix [38]
The correct answer is the fourth option. The nervous system is the system in the body which can be affected by ionizing radiation. Exposure to this kind of radiation may lead to changes in motor function or neurological disorders.
5 0
3 years ago
Consider the intermediate chemical reactions. 2 equations. First: upper C a (s) plus upper C upper O subscript 2 (g) plus one ha
DochEvi [55]

<u>Answer:</u> When the enthalpy of this overall chemical equation is calculated, the enthalpy of the second intermediate equation is halved and has its sign changed.

<u>Explanation:</u>

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.

The overall chemical reaction follows:

CaO(s)+CO_2\rightarrow CaCO_3(s)     \Delta H^o_{rxn}=?

The intermediate balanced chemical reaction are:

(1) Ca(s)+CO_2(g)+\frac{1}{2}O_2(g)\rightarrow CaCO_3(s)    \Delta H_1=-812.8kJ  

(2) 2Ca(s)+O_2(g)\rightarrow 2CaO(s)     \Delta H_2=-1269kJ

The expression for enthalpy of the reaction follows:

\Delta H^o_{rxn}=[1\times (\Delta H_1)]+[\frac{1}{2}\times (-\Delta H_2)]

Hence, when the enthalpy of this overall chemical equation is calculated, the enthalpy of the second intermediate equation is halved and has its sign changed.

3 0
3 years ago
Why are gamma rays not affected by a magnet as they Passover it
avanturin [10]
Gamma rays are not magnetic
7 0
4 years ago
Read 2 more answers
a book with a mass of 1 kg is dropped from a height of 3 m. what is the potential energy of the book when it reaches the floor?
mafiozo [28]
Well, first of all, the formula for finding potential energy is;
PE=mgh
  Where; m is the mass
               g is the gravitational force or acceleration due to gravity
                h is the height. 
   Anyway, according to the question, the mass is 1kg, the acceleration due to gravity has a constant value of 10ms² . And the height is 3m. Now you just have to use all these in the formula. So;
mgh= 1 x 10 x 3. That will be 30. And the unit of potential energy is Joule. So the answer is 30 joules. Hope i helped. Have a nice day.     
5 0
3 years ago
How many molecules of NH3 are produced from 4.72x10 negative 4 power g of H2?
Delvig [45]
<span>9.40x10^19 molecules.
   The balanced equation for ammonia is:
 N2 + 3H2 ==> 2NH3
   So for every 3 moles of hydrogen gas, 2 moles of ammonia is produced. So let's calculate the molar mass of hydrogen and ammonia, starting with the respective atomic weights:
 Atomic weight nitrogen = 14.0067
  Atomic weight hydrogen = 1.00794

   Molar mass H2 = 2 * 1.00794 = 2.01588 g/mol
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   Moles H2 = 4.72 x 10^-4 g / 2.01588 g/mol = 2.34140921086573x10^-4 mol
   Moles NH3 = 2.34140921086573x10^-4 mol * (2/3) = 1.56094x10^-4 mol

Now to convert from moles to molecules, just multiply by Avogadro's number: 1.56094x10^-4 * 6.0221409x10^23 = 9.400197448261x10^19
   Rounding to 3 significant figures gives 9.40x10^19 molecules.</span>
7 0
3 years ago
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