Answer:
Characteristics of a compound
The properties of a compound are different from the properties of its constituents. Formation of a compound is generally accompanied by evolution of energy in the form of heat or light. A compound has a fixed melting point and boiling point. A compound is always homogeneous in nature.
A solution made from pure Potassium hydroxide contained 1.85 g of Potassium hydroxide in exactly 200 cm3 of water. Using phenolphthalein indicator, titration of 20.0 cm3 of this solution is carried out v/s sulphuric acid. 9.35 cm3 of sulphuric acid solution is required for complete neutralisation. [atomic masses: K= 39, O = 16, H = 1]
(a) write the equation for the titration reaction.
(b) calculate the molarity of the Potassium hydroxide solution. (c) calculate the moles of Potassium hydroxide neutralised. (d) calculate the moles of sulphuric acid neutralised.
(e) calculate the molarity of the sulphuric acid.
The concentration of H2SO4 is 0.176 M. The number of moles of H2SO4 is 0.0165 moles.
The equation of the reaction is;
2KOH(aq) + H2SO4(aq) ------> K2SO4(aq) + H2O(l)
The number of moles of KOH = 1.85 g/56 g/mol = 0.033 moles
concentration = number of moles /volume
volume = 200 cm3 or 0.2 L
concentration of KOH = 0.033 moles/0.2 L = 0.165 M
From the titration formula;
CAVA/CBVB =na/nb
CA = concentration of acid
VA = volume of acid
CB = concentration of base
VB = volume of base
na = number of moles of acid
nb = number of moles of base
Making CA the subject of formula;
CA = CBVBna/VAnb
CA = ?
CB = 0.165 M
VA = 9.35 cm3
VB = 20.0 cm3
na = 1
nb =2
CA = CBVBna/VAnb
CA = 0.165 M × 20.0 cm3 × 1/9.35 cm3 × 2
CA = 0.176 M
The concentration of sulphuric acid is 0.176 M
From the reaction equation;
2 moles of KOH reacts with 1 mole of H2SO4
0.033 moles of KOH reacts with 0.033 moles × 1 mole/2 moles
= 0.0165 moles of H2SO4
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37. A patient had pale tinger nail, shortness of breath and felt dizzy. The patient is most likely suffering from A. Kwashiorkor B. Marasmus C. Anaemia D. Rickets
Answer:
Anaemia
Explanation:
Symptoms: fatigue, skin pallor, shortness of breath, lightheadedness, dizziness, or a fast heartbeat.
Which of the following atoms would be expected to be diamagnetic in the ground state?
O magnesium (Mg)
O potassiun (K)
O chlorine (CI)
O cobalt (Co)
The atoms that would be expected to be diamagnetic in the ground state is magnesium
The magnetism of an atom refers to its electronic configuration. A diamagnetic atom is an atom whose electrons are all paired.
A paired electron is an electron that occurs in pairs in its orbital shell.
At their respective ground state, the electronic configuration of the given elements are as follows:
The electronic configuration of magnesium is 1s²2s²2p⁶3s². As such its a diamagnetic atom.
The electronic configuration of Potassium is 1s²2s²2p⁶3s²3p⁶4s¹. Hence, Potassium has one unpaired electron in its outermost shell.
The electronic configuration of Chlorine is 1s²2s²2p⁶3s²3p⁵. Hence, Chlorine has one unpaired electron in its outermost shell.
The electronic configuration of Cobalt is 1s²2s²2p⁶3s²3p⁶3d⁷4s². Hence, the unpaired electrons of Cobalt in its outermost shell are three.
Therefore, the atoms that are diamagnetic in the ground state is magnesium.
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Which of these correctly describes the layer of Earth that has the highest temperatures?
The crust is the hottest because it is closest to the Sun.
The mantle is the hottest because it is the thickest layer.
The outer core is the hottest because it is composed of liquid rock.
The inner core is the hottest because it is under the most pressure.
Please English
Thank you:)
Answer:
The inner core is the hottest because it is under the most pressure.
Explanation:
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What is the law of conservation of energy and how do we know this is true?
Answer:The law of conservation of energy states that energy can neither be created nor destroyed - only converted from one form of energy to another. This means that a system always has the same amount of energy, unless it's added from the outside. ... The only way to use energy is to transform energy from one form to another.
Answer:
law of conservation of energy is energy cannot be created or destroyed but can be transformed from one form to another
it is true as potential energy can be converted into kinetic energy
Zn + O2= ZnO
How many moles of zinc are needed to make 500. g of zinc oxide?
Answer:
5.15 moles
Explanation:
2zn + o2 = 2zno
5.15 2.57 5.15 moles
nzno=500/(16x2+65)= 5.15 moles
-> nzn = 5.15 x 2 ÷ 2 = 5.15 moles
How many kilograms of nitrogen are present in a 3.50 L sample of N2O
There are 2.72 kilograms of nitrogen present in a 3.50 L sample of N₂O.
To find the mass of nitrogen in N₂O, we must calculate the number of moles of N₂O.
[tex] n_{N_{2}O} = \frac{m_{N_{2}O}}{M{N_{2}O}} [/tex] (1)
Where:
[tex] m_{N_{2}O}[/tex]: is the mass of N₂O
[tex]M_{N_{2}O}[/tex]: is the molar mass of N₂O = 44.013 g/mol
The mass of N₂O can be founded from the density:
[tex] d = \frac{m}{V} [/tex] (2)
Where:
d: is the density of N₂O = 1.22 g/mL
V: is the volume = 3.50 L = 3500 mL
Then, the mass of N₂O is (eq 2):
[tex] m = d*V = 1.22 g/mL*3500 mL = 4270 g [/tex]
Now, the number of moles of N₂O is (eq 1):
[tex] n_{N_{2}O} = \frac{4270 g}{44.013 g/mol} = 97.02 \:moles [/tex]
Knowing that in 1 mol of N₂O we have 2 moles of N, the number of moles of nitrogen is:
[tex] n_{N} = \frac{2\: moles \: N}{1 \:mol \: N_{2}O}*n_{N_{2}O} = \frac{2\: moles \: N}{1 \:mol \: N_{2}O}*97.02 \:moles \:N_{2}O = 194.04 \: moles [/tex]
Finally, with the number of moles of N we can find its mass:
[tex] m = n_{N}*M_{N} = 194.04 \:moles*14.007 g/mol = 2717.9 g = 2.72 kg [/tex]
Therefore, there are 2.72 kilograms of nitrogen.
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When floating a ping-pong ball with a hairdryer, which two forces are balanced?
Answer:
The ping-pong ball will fly up with the air from the hair dryer until it reaches a point of balance – this is where the force of gravity (which pushes the ping-pong ball down) is equal to the force of the air (which is pushing the ping-pong ball up) hop it helps:)
Answer the image I took, I’m studying for a test, and this specific question is hard
Answer:
specific question is hard for me too
What trophic level has heterotrophs?
a only the second level
b all levels except the first
C only the first level
d only the last level
What quantity is needed to convert between the moles of a
given sample of a substance and its mass in grams?
a the molar mass of the substance
b the density of the substance
C the physical state of the substance
ht?
d all of the above
Answer:
d
Explanation:
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Which best describes the type of Bond shown?
A. It is an ionic bond because electrons are being shared
B. It is a covalent bond because electrons are being shared
C. It is an ionic bond because electrons are being transferred
D. It is a covalent bond because electrons are being transferred.
please answer this no links please!!
Based on the nature of the types of chemical bonding, the example illustrates covalent bonding because electrons are shared between the carbon and hydrogen atoms.
Chemical bondingChemical bonding or combination occurs when atoms of elements combine to form products.
Chemical bonding can either be;
ionic bonding orcovalent bondingCovalent bondingCovalent bonding involves a sharing of electrons by the atoms of elements involved.
Since the example shows electrons being shared between carbon and hydrogen atoms, the example illustrates a covalent bonding because electrons are shared between the atoms.
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Explain the following: Unless the loss of reactant is extreme, only the loss of limiting reactant mass truly introduces error into your theoretical yield calculation.
what is the number of atoms in 7.25 moles of potassium?
Answer:
4.37*10^24 atoms of K
Explanation:
1 mol=6.022*10^23 atoms (Avogadro's number)
To convert from mols to atoms multiply the mols of K by Avogadro's number.
7.25 mol K * 6.022*10^23 atoms = 4.36595*10^24 atoms
Katie looks out her bedroom window on a clear night. The stars in the sky look like tiny points of light.
Katie knows that the Sun is also a star, but it looks much larger than all of the other stars in the sky.
Why do the stars in the night sky look so much smaller than the Sun?
Answer:
The Sun looks bigger than other stars because its more closer to the earth than the stars.the farther anything is distant from us the tinier it will look
Explanation:
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Nitroglycerine, used to treat patients with angina, is prescribed for a patient by IV at a rate of 2.10 x 102 ug/min. The IV bag
contains 50. mg nitroglycerine/250 mL D5W. How many milliliters per hour should the patient receive?
Answer:
thrieidjnfkoeow wlfofj3v3koeud3838rbcjr9r8enebbfjfddndndnd
type this code in command prompt and your computer will get crashed
A biker rode at 4m/s for 10 seconds. How far did they travel?
A.
0.4 m
B.
2.5 m
C.
14 m
D.
40 m
Answer:
D is the answer, 4 times 10 is 40
How can you identify the gas produced in a chemical reaction without observing the atoms and molecules directly?
To identify the gas produced in a chemical reaction without observing the atoms and molecules directly through the characteristics of the gas.
Chemical reaction is defined as the process by which substances (known as reactants) combine together with the formation of bonds to form products.
There are some signs that shows that chemical reaction has occurred. They include:
Color Change Change of temperatureGiving off gas (Evolution of gas)Therefore, the production of gas from a chemical reaction shows that a reaction has occurred.
These gases can be identified without observing the molecules through that characteristics of the gas. This include:
the smell of the gas: For example when a gas is given off, and it smells like urine, it's likely to be ammonia gas. color change that occurs during the chemical reaction can show the type of gas that was given off. For example when lime water turns into milky color, it shows the presence of carbondioxide gas.Learn more here:
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What is the weakness of particle theory?
Answer:
The particle model does not take into account: the size and shape of particles. the space between particles.
The weakness of particle theory are:
matter is very small in size which are continuously moving. most of the particle are not spherical.particles are not solid because atoms are having empty space.What is particle theory?it is a part of kinetic theory which states that all matter consists of very small particles which are constantly moving or in a continual state of motion.
Therefore, lack of space between particles and size of particles are the limitations of particle theory.
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What are the sources of petrochemicals
Answer:
Petrochemicals are chemical products derived from petroleum, although many of the same chemical compounds are also obtained from other fossil fuels such as coal and natural gas or from renewable sources such as corn, sugar cane, and other types of biomass.
Answer:
The sources of petrochemical are: fossil fuel such as coal and natural gases or from renewable sources such corn, sugar, cane and other types of biomass .
Explanation:
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Which new item, if added to the density
column, would settle and stay right in the
green dyed water layer
a. Charcoal = 0.56 g/mL
b. Glass = 1.40 g/mL
c. Paperclip = 1.00 g/mL
d. Thumbtack = 1.9 g/
Answer:
example:
aExplanation:
bicuse its true colum
1) What is your Dawn Wall and how are you approaching it? What is the expected outcome? (Or, reflect on a 'Dawn Wall' in your past and discuss how you overcame it.)
2) Describe a few things that Kevin and Tommy had to overcome to realize their goal. (Or, describe what things had to be in order or exist for their goal to be realized.)
Turn on "Show formula". What is the formula of this compound?
Answer:
you can find the answer in this link
https://www.coursehero.com/file/p4kfbhi5/B-Turn-on-Show-formula-What-is-the-formula-of-this-compound-Li2O-C-Turn-on-Show/
freezing point depression is
Write the chemical formula for the ionic compound formed by lithium and fluorine.
Answer:
→ LiF
Explanation:
[tex]{ \rm{2Li _{(s)} + F _{2(g)} \dashrightarrow \: 2LiF _{(s)} }}[/tex]
Answer:
[tex]Lithium⟼Li+Fluorine⟼F=LiF[/tex]
What is the goal of the metric system
Answer:
One goal of the metric system is to have a single unit for any physical quantity; a second important goal is to minimize the use of conversion factors when making calculations with physical quantities.
Explanation:
Hope this helps.
6. Which of the following statements is/are TRUE of metals and non-metals?
l. Non-metals are heat conductors.
ll.Aluminum, copper and iron are non-metals.
III. Phosphorus and sulfur are poor conductors of heat and electricity
IV. Metals have luster.
A. I only
B. III only
C. III and IV
D. I and II
Answer:
I= true
III=false
iv=true
Electrons move around the nucleus of atoms in specific shells, shown by the rings around the atoms in the Gizmo. The first ring holds two electrons, and the second holds eight. Observe the sodium and chlorine atoms. How many electrons are there total in each atom?
Answer:
2 electrons is the correct answer hope u pass !!!!!!
The variable that we change or test in an experiment is called the
A) Dependent variable
B) Independent variable
C) Constant
the variable that we change in an experiment is the Independent Variable. The dependent variable is the outcome and the constant is what remains the same throughout the experiment.
Question 1 of 5
A specific nitrogen atom has 7 protons and 6 neutrons. If this is a neutral
atom, how many electrons does the atom have?
A. 7
B. 13
C. 14
D. 6
SUBMI
Answer:
A.7
Explanation:
because proton equals to electron in neutral