Granite forms when magma cools slowly underground. Granite ____

Consider the following isotopic symbol: 137Ba2+

aliya0001 [1]

Answer:

a) 56 protons

b) 54 electrons

c) 81 neutrons

d) The sum of protons and neutrons is shown. The number of protons is always the same. So we can calculate the number of neutrons ( and also the isotopes)

e)137Ba (with 56 protons and 81 neutrons)

f) atomic mass is 136.9 u ; the mass number is the sum of protons and neutrons and is 137

Explanation:

Step 1: Data given

137 Ba2+ is an isotope of barium. The atomic number of barium( and its isotopes) is 56. This shows the number of protons.

For a neutral atom, the number of protons is equal to the number of electrons.

The different isotopes of an element have the same number of protons but a different number of neutrons.

137Ba2+ has 56 protons (this is the same as the atomic number)

137Ba2+ has 54 electrons ( since it's Ba2+, this means it has 2 electrons less than protons, that's why it's charged +2)

137Ba2+ has 81 neutrons ( 137 - 56 = 81)

In the symbol, the atomic number is not shown. The sum of the protons and neutrons is shown. (Since the number of protons is the same for every isotope, we can calculate the number of neutrons that way. By knowing the neutrons, we also know the isotope.

This isotope is 137Ba

Atomic mass is also known as atomic weight. The atomic mass is the weighted average mass of an atom of an element based on the relative natural abundance of that element's isotopes.

The atomic mass of 137Ba2+ is 136.9 u

The mass number is a count of the total number of protons and neutrons in an atom's nucleus.

The mass number of 137Ba2+ is 137

3 0

3 years ago

If a sample of 0.150 g of kcn is treated with an excess of hcl, calculate the amount of hcn formed in grams.

blondinia [14]

<h2> The amount of Hcn formed in grams is = 0.06223 grams</h2><h3> calculation</h3>

write the equation for reaction

that is; KCn + HCl → KCl + HCn

step 1:find the moles of KCn reacted

moles of KCn = mass of KCn/molar mass of KCn( 65.12 g/mol)

= 0.150 g/ 65.12 g/mol =2.303 x10^-3 moles

step 2: use the mole ratio between KCn :HCn which is 1:1 to determine the moles of HCn which is also 2.303 x 10^-3 moles

step 3: find the mass of HCn =moles of HCn x molar mass of HCn

= 2.303 x10^-3 x 27. 02 =0.06223 grams

3 0

4 years ago

Question 1 (Matching Worth 3 points)

Misha Larkins [42]

Answer:

Question 1: 1) Increasing the pressure C) Shift to the right

2) Removing hydrogen gas A) Shift to the left

3) Adding a catalyst B) No effect

Question 2: This reaction is exothermic because the system shifted to the right on cooling.

Question 3: Shift it toward the reactants.

Question 4: Adding more of gas C to the system.

Question 5: It will shift toward the reactant side because the reactant side has one more mole of gas than the product side.

Question 6: True.

Question 7: there is no suitable choice is provided.

We can shift the equilibrium toward the right via:

Increasing N2O3 concentration,

decreasing NO and/or NO2 concentration,

decreasing the pressure,

lowering the T (cooling the system).

Explanation:

Question 1: Match the action to the effect on the equilibrium position for the reaction N2(g) + 3H2(g) ⇌ 2NH3(g).

Match Term Definition

Removing ammonia A) No effect

Removing hydrogen gas B) Shift to the left

Adding a catalyst C) Shift to the right

Le Châtelier's principle states that when there is an dynamic equilibrium, and this equilibrium is disturbed by an external factor, the equilibrium will be shifted in the direction that can cancel the effect of the external factor to reattain the equilibrium.

1) Increasing the pressure:

When there is an increase in pressure, the equilibrium will shift towards the side with fewer moles of gas of the reaction. And when there is a decrease in pressure, the equilibrium will shift towards the side with more moles of gas of the reaction.

The reactants side (left) has 4.0 moles of gases and the products side (right) has 2.0 moles of gases.

So, increasing the pressure will shift the reaction to the side with lower moles of gas (right side).

so, the right match is: C) Shift to the right.

2) Removing hydrogen gas:

Removing hydrogen gas will decrease the concentration of the products side, so the reaction will be shifted to the lift side to suppress the decrease in the concentration of hydrogen gas by removing.

so, the right match is: A) Shift to the left.

3) Adding a catalyst:

Catalyst increases the rate of the reaction without affecting the equilibrium position.

Catalyst increases the rate via lowering the activation energy of the reaction.

This can occur via passing the reaction in alternative pathway (changing the mechanism).

The activation energy is the difference in potential energies between the reactants and transition state (for the forward reaction) and it is the difference in potential energies between the products and transition state (for the reverse reaction).

in the presence of a catalyst, the activation energy is lowered by lowering the energy of the transition state, which is the rate-determining step, catalysts reduce the required energy of activation to allow a reaction to proceed and, in the case of a reversible reaction, reach equilibrium more rapidly.

with adding a catalyst, both the forward and reverse reaction rates will speed up equally, which allowing the system to reach equilibrium faster.

so, the right match is: B) No effect.

Question 2: Nitrogen dioxide gas is dark brown in color and remains in equilibrium with dinitrogen tetroxide gas, which is colorless.

2NO2(g) ⇌ N2O4(g)

When the light brown color equilibrium mixture was moved from room temperature to a lower temperature, the mixture turned lighter brown in color. Which of the following conclusions about this equilibrium mixture is true?

Moving from room temperature to a lower temperature, means that the T is decreased.

The mixture turned lighter brown in color, means that the reaction is shifted towards the products side.

Moving towards the product side, means that we decreased the concentration of the product side, which ,means that the heat is evolved from the reaction and the reaction is exothermic.

So, the right choice is: This reaction is exothermic because the system shifted to the right on cooling.

Question 3: According to Le Châtelier's principle, how will a decrease in concentration of a reactant affect the equilibrium system?

A decrease in the reactants concentration will disturb the equilibrium position of the system. To attain the equilibrium again, the system will be shifted to the lift (reactants side) to increases the concentration of the reactants and attain the equilibrium again.

So, the right choice is: Shift it toward the reactants.

Note: The answer of Q 4, 5, 6 & 7 and all answers are in the attached word file.

Download docx

5 0

4 years ago

_______at astronomical observatories capture this light even better, providing a clearer picture of our galaxy.

ozzi

Answer:

asrsrhWrrgrefev

Explanation:

DVF HTUKTYGFGZERGQMHMTU6U78O78XCSDBSDBDSVSD∈∈∈∈∈∈∈∵∵∵∵∵∵∵¬¬¬¬¬¬¬¬¬¬¬㏒㏒㏒㏒㏒㏒㏒㏒㏒㏒㏒㏒㏒㏒㏒㏒㏑㏑㏑㏑㏑㏑㏑㏑㏑㏑㏑㏑㏑㏑㏑㏑㏑㏑∞∞∞∞∞∞∞∞.

6 0

3 years ago

What is the true ratio of atoms in a molecule or formula unit called?

Colt1911 [192]

Answer:

O the molecular formula

Explanation:

The true ratio of atoms in a molecule or formula unit is called the molecular formula.

The molecular formula of a compound shows the true number of atoms that are combining to form a compound.

For example, the molecular formula of water is H₂O.

Empirical formula of a compound is its simplest ratio.
When the number of atoms are divided by the smallest possible factor, it yields the empirical formula.

3 0

3 years ago

Granite forms when magma cools slowly underground. Granite _____.