I suppose you mean to ask why we can't go through obstacles.
Any atom is surrounded by an electronic cloud. When two atoms get close to each other, the electronic clouds repel each other, preventing them from interpenetrating each other. That same phenomenon, on a larger scale, prevents us from going through matter.
Answer:
See explanation
Explanation:
A reaction in which heat and light are produced is a combustion reaction. Combustion is said to have occurred when a substance is burnt in oxygen.
The balanced equation of the reaction is;
4Li(s) + O2(g) ------->2Li2O(s)
This reaction is exothermic because heat was produced. The reaction has a low activation energy as the metal easily burst into flames in oxygen. A catalyst is not needed in this reaction because it has a low activation energy.
According to the law of conservation of mass. Atoms are neither created nor destroyed in a chemical reaction. What this means is that in a chemical reaction, the number of atoms of each element on the left hand side must be the same as the same as the number of atoms of the same element on the right hand side.
Answer:
Given that W=mg:
The weight of the box would be 50 N taking the value of 'g' as 10ms-2. Taking the value of 'g' as 9.8ms-2, the weight of the box would be 49 N.
(N = Newtons)
Considering the ideal gas law, there are 279.42 moles of acetylene in the tank.
<h3>Definition of ideal gas</h3>
Ideal gases are a simplification of real gases that is done to study them more easily. It is considered to be formed by point particles, do not interact with each other and move randomly. It is also considered that the molecules of an ideal gas, in themselves, do not occupy any volume.
<h3>Ideal gas law</h3>
An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of gases:
P×V = n×R×T
<h3>Moles of acetylene</h3>
In this case, you know:
- P= 1765 kPa= 17.4192 atm (being 101.325 kPa= 1 atm)
- V= 390 L
- n= ?
- R= 0.082

- T= 23.5 °C= 296.5 K (being 0 °C= 273 K)
Replacing in the ideal gas law:
17.4192 atm× 390 L = n×0.082
× 296.5 K
Solving:

<u><em>n= 279.42 moles</em></u>
Finally, there are 279.42 moles of acetylene in the tank.
Learn more about ideal gas law:
brainly.com/question/4147359
Answer and Explanation:
Polar compounds are those that have an unequal sharing of electrons, causing one end to be more positively or negatively charged than the other end.
Ionic compounds are those that are made up of a positive ion and a negative ion. Clearly, we can see that if one ion is positive and the other is negative, then that would make one end of the compound more or less positively charged than the other end, which is exactly the definition of a polar compound.
That is why ionic compounds are always polar.