Answer:
The statements that describe Mg are:
1. is very reactive as a metal
2. forms a basic solution in water
3. is found in nature only combined with other elements
Explanation:
Magnesium is a s-block chemical element that belongs to group 2 and period 3 of the periodic table. It is a reactive alkaline earth metal that exists in nature only in the combined state with elements such as carbon, calcium and oxygen.
Magnesium reacts with water at room temperature, to give strongly basic metal oxide of the formula, MgO, which forms a basic solution in water.
It also reacts vigorously with halogens such as chlorine and bromine, to form salts.
Magnesium is a highly reactive alkaline earth metal that forms a basic solution in water and can react vigorously with alkali metals to form salts. It consists of diatomic molecules in its elemental form.
Magnesium is one of the alkaline earth metals, which are found in Group 2 of the periodic table. It is a highly reactive metal that forms a basic solution in water and can react vigorously with alkali metals to form salts. Magnesium also consists of diatomic molecules in its elemental form. However, it is not one of the least reactive elements; rather, it is one of the more reactive elements in Group 2.
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Answer: Option (c) is the correct answer.
Explanation:
Entropy is defined as the degree of randomness that is present within the particles of a substance.
As is ionic in nature. Hence, when it is added to water then it will readily dissociate into ammonium ions () and nitrate ions ().
Therefore, it means that ions of ammonium nitrate will be free to move from one place to another. Hence, there will occur an increase in entropy.
Thus, we can conclude that ammonium nitrate () dissolve readily in water even though the dissolution process is endothermic by 26.4 kJ/mol because the overall entropy of the system increases upon dissolution of this strong electrolyte.
byCpm/(JK-1mol-1) = 91.47
+7.5x10-2(T/K). In a particular experiment,
1.0molCHCl3 is heated from 273K to 300K. Calculate the
changein molar entropy of the sample.
Answer : The change in molar entropy of the sample is 10.651 J/K.mol
Explanation :
To calculate the change in molar entropy we use the formula:
where,
= change in molar entropy
n = number of moles = 1.0 mol
= final temperature = 300 K
= initial temperature = 273 K
= heat capacity of chloroform =
Now put all the given values in the above formula, we get:
Therefore, the change in molar entropy of the sample is 10.651 J/K.mol
b.. Different kinds of elements have different kinds of atoms.
c..The protons, neutrons and electrons are different for different kinds of atoms.
d... An atom always has the same number of protons and electrons.
e... An atom always has the same number of protons and neutrons.
f.... Atoms have no mass because they are very small.
Q2 .Compare the Rutherford's model and the Bohr's model of the atom. State one similarity and one difference between them.
Q3..what observation from rutherford's gold foil experiment made him conclude that an atom has a tiny but dense nucleus that is positively charged?
Q4.. Explain why the nucleus of an atom is positively charged, while the atom is electrically neutral.
Q5...The symbols and atomic numbers of three elements are as follows:
Ne Atomic number 10
A/ Atomic number 13
K Atomic number 19
a.. identify each element from its symbol.
b.. How many protons and electrons does an atom of each element have?
c.. Draw the electronic structure of the atom of each element.
Answer:
a. false
b. true
c. false
d. false
e. false
f. false
Q2: Both have electrons orbiting around the nucleus; Bohr's model is more detailed and expands on Rutherford's
Q5:
a.
Ne = neon
Al = aluminum
K = potassium
b.
Ne = 10 electrons/protons
Al = 13 electrons/protons
K = 19 electrons/protons
Given:
Rivet diameter, = 1.872 cm
Hole diameter, = 1.870 cm
Temperature, = 22 °C
Formula Used:
where,
= coefficient of linear expansion
= change in diameter =
= change in temperature =
Solution:
we know that coefficient of linear expansion of steel, =
Using the above formula :
= \frac{1.870 - 1.872}{1.872\times \T_{2} - T_{1}}[/tex]
= \frac{1.870 - 1.872}{12\times 10^{-6}}}[/tex]
Therefore, the rivet must be cooled to
The question involves the concept of thermal expansion in Physics. By knowing the initial diameter of the rivet and hole, as well as the ambient temperature, we can use the thermal expansion formula to calculate the temperature to which the steel rivet must be cooled to fit into the hole.
The subject in question pertains to Physics and specifically to the concept of thermal expansion. This indicates how objects (in this case, a steel rivet) tend to change in volume or shape as a response to a change in temperature. The diameter of the rivet when cooled will decrease slightly, allowing it to fit into the smaller hole.
To find the temperature to which the rivet needs to be cooled, we require knowledge of the thermal expansion coefficient of steel, which (for generalization) can be averaged to around 0.000012 (1/°C). The formula to calculate the change in diameter (Δd) is:
Δd = α * d * ΔT
where α is the coefficient of linear expansion, d is the original diameter, and ΔT is the change in temperature. Knowing the initial diameter of the rivet and the hole it must fit into, together with the ambient temperature (22°C), we can rearrange this formula to find the cooling temperature needed for the rivet to fit into the hole.
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a compass needle points north toward earths magnetic pole is an example of the electromagnetic force.
An electromagnetic force is one of the four fundamental forces a combination of both electrical and magnetic forces and this force is act up on the charged particles .
It is inversely proportional to the inverse square of the distance between particles, electromagnetic force can be attractive or repulsive shows infinite range and this force holds atoms together in molecules.
This force can be produced by electromagnetic fields, electrostatic field, and magnetostatic field which affects all of the universal objects due to its infinite range.
This force causes electric and magnetic effects like repulsion between like electrical charges or the interaction of bar magnets, it is weaker than the strong force.
For more details regarding electromagnetic force, visit
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answer:
a compass needle points north toward earths magnetic pole.
Explanation:
because of the earths magnetic field.