Answer:
valancy
Explanation:
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Pretest: Chemical Reactions
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Which coefficient of O, is needed to balance the equation C3Hg+ 02 - 3C02 + 4H2O?
OA. 2
OB. 3
O c. 5
OD 6
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The coefficient of oxygen is five which is needed to balance the given chemical equation and equation is C₃H₈ +5 O₂[tex]\rightarrow[/tex] 3 CO₂ +4 H₂O.
Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.
A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .
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are protons attracted to neutrons or electrons or both?
Answer:
protons and electrons attract each other.
Explanation:
neutron as no charge, proton and electron are exactly the same size but opposite. ( the opposite charge attract)
The protons possess a positive charge so they attract negatively charged electrons.
What is a proton?A proton can be described as a stable subatomic particle, a symbol with a positive charge of +1e elementary charge. Proton's mass is slightly less than that of a neutron but 1836 times the mass of an electron.
Protons and neutrons are jointly referred to as "nucleons" each with masses of approximately one atomic mass unit. More than one proton can be present in the nucleus of an atom. They give the attractive electrostatic central force which holds the atomic electrons.
The number of protons in the nucleus is referred to as the atomic number and is represented by the symbol Z. Since each element in the modern periodic table has a unique number of protons, its own unique atomic number, determines the chemical characteristics of the element.
As the neutrons are neutral do not carry any charge so the protons do not attract neutrons.
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phenolphthalein is used as a visual indicator in a strong acid-strong base titration because
The pH range of phenolphthalein is 8.3 - 10.0, which is suitable with the pH range of Strong Acid and Strong base titration and so phenolphthalein is used as a visual indicator in a strong acid-strong base titration.
What is an Indicator ?Any substance that gives a clear visible indication of the presence or absence of a particular concentration of a chemical species, such as an acid or an alkali in a solution, usually by a colour change.
The pH range of Strong Acid and Strong base titration is 3–11 and equivalent point is at 7
the pH range of Strong Acid and Weak base titration, is 3–8 and equivalent point is below 7
the pH range of Weak Acid and Strong base titration, is 6 - 11 and equivalent point is above 7
So for titration , an indicator with suitable pH range is used
The pH range of phenolphthalein is 8.3 - 10.0.
Therefore phenolphthalein is used as a visual indicator in a strong acid-strong base titration.
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How long should you monitor a person who shows signs of a mild allergic reaction
Answer:
Most reactions occur quickly after ingestion or contact with the allergen, but some can occur up to a few hours later. There can also be a second phase of the reaction when symptoms reoccur. It is important to keep an eye on your child for about 6-8 hours following the first reaction.
Explanation:
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Iron (II) chloride
Covalent or ionic
Answer:
ionic
Explanation:
Iron(II) chloride, also known as ferrous chloride, is the chemical compound of formula FeCl2. It is a paramagnetic solid with a high melting point. The compound is white, but typical samples are often off-white
1) pbo+co-->pb+co2 which type of reaction is this?
a) redox reaction
b) oxidation reaction
c) reduction reaction
d) none of the above
PbO + CO → Pb + CO₂
Oxidation States of the Elements
Reactants Products
Pb +2 0
O -2, -2 -4
C +2 +4
Since the oxidation state/number of Pb decreased, it is being Reduced.
Since the oxidation state/number of C increased, it is being Oxidized.
∴ this is a Redox Reactionwhat is the molar mass of dimethylglyoxime, c4h8n2o2?
Answer: 116.12 g/mol
Explanation:
The molecular mass of a formula unit of dimethylglyoxime is calculated as 116 g/mol.
What is molecular mass?The molecular mass can be given as the sum of the mass of each element in the formula unit of the compound.
The dimethylglyoxime is the compound with molecular formula, [tex]\rm C_4H_8N_2O_2[/tex].
The mass of each element in the compound is:
Carbon = 12 gramsHydrogen = 1 gramsNitrogen = 14 gramsOxygen = 16 gramsSubstituting the mass in the formula unit of the compound as:
[tex]\rm C_4H_8N_2O_2=4(carbon)+8(hydrogen)+2(nitrogen)+2(oxygen)\\ C_4H_8N_2O_2=4(12)+8(1)+2(14)+2(16)g\\ C_4H_8N_2O_2=116\;g[/tex]
The molecular mass of dimethylglyoxime is 116 g/mol.
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How many energy levels does iron have
Answer:
Number of Energy Levels: 4
First Energy Level: 2
Second Energy Level: 8
Third Energy Level: 14
Fourth Energy Level: 2
Explanation:
Hope It Helps!
Answer:
4 energy levels
Explanation:
1st energy level = 2 electrons
2nd energy level = 8 electrons
3rd energy level = 8 electrons
4th energy level = 8 electrons
Copper has two naturally occurring isotopes: Cu-63 with mass 62.9395 amu and a natural abundance of 69.17% and Cu-65 with mass 64.9278 amu and a natural abundance of 30.83%. Calculate the atomic mass of copper.
Answer
63.55
Explanation:
63
C
u
has
69.2
%
abundance.
65
C
u
has
30.8
%
abundance.
So, the weighted average is
62.93
×
69.2
%
+
64.93
×
30.8
%
How do you know where something fits on the electromagnetic spectrum? I currently have the Hz but do I need to convert that into something else?
tại sao lại có cầu vồng
Answer:
because of the reflection that the Sun makes on the water after it rained.
bởi vì sự phản chiếu mà mặt trời tạo ra trên mặt nước sau khi trời mưa
Explanation:
Which statement(s) correctly compare the masses of protons, neutrons, and electrons? Select two options.
1. Protons and neutrons have similar mass.
2. Protons and electrons have similar mass.
3. Neutrons and electrons have similar mass.
4. Protons are smaller than a neutron or an electron.
5. Neutrons are smaller than a proton or an electron.
6. Electrons are smaller than a proton or a neutron.
Answer:
6 Electrons r smaller than a proton or a neutron
Answer:
1st and last one
Explanation:
when the n quantum number equals 1, we are in what orbital?
Answer:
p orbital
Explanation:
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What is the molarity of 930 mL of LiCl solution that contains 139.9 g of LiCI?
A. 3.5 mol/L
B. 150 mol/L
C. 3.3 mol/L
D. 3.5 x 10-3 mol/L
Explanation:
To determine the molarity, we have to find the number of moles in the volume given, and then extrapolate to find the number of moles that would be in 1 L.
Determine the moles in the given volume
moles of LiCl = mass ÷ molar mass
= 139.9 g ÷ 42.39 g/mol
= 3.30 mol
Find the moles in 1 L
Since 930 mL of LiCl = 3.30 mol
then 1000 mL of LiCl = (3.30 mol × 1000 mL/L) ÷ 930 mL
= 3.55 mol/L
2. Describe the difference between:
(a) a group and a period
Answer:
A group is a vertical row on the periodic table and a period is a horizontal row on the periodic table.
Explanation:
Answer:
A group on the periodic table refers to the vertical arrangement of the elements while a period refers to the horizontal rows of elements
Using the synopsis of the article, which of the following is a true statement?
Question 1 options:
Scientists determined the Earth has a metallic liquid core and confirmed their theory.
Scientists work independently to form theories about the Earth without sharing data.
Scientists have updated their original models of the Earth’s interior to reflect new discoveries.
Scientists developed an evidence-based model showing the Earth has a solid outer and inner core.
Answer: Scientists work independently to form theories about the Earth without sharing d
Scientists work independently to form theories about the Earth without sharing data.
What is solar system?Solar system is defined as the grouping of the eight planets and their moons in orbit around the sun, as well as other smaller bodies like comets, asteroids, and meteoroids.
It can also be defined as the Sun's orbiting objects are confined by gravity to one system.
An orbiting collection of planets, meteors, or other celestial bodies is referred to as a star system.
The Sun, an ordinary star, the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto make up our solar system.
Our solar system is referred to as the "solar system" because our Sun is called Sol after the Latin word for Sun, "solis," and because anything related to the Sun is termed "solar."
Thus, scientists work independently to form theories about the Earth without sharing data.
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who is generally called the father of modern chemistry
Explanation:
Antoine Lavoisier is the answer
Answer:
Antoine Lavoisier is the father of chemistry
Explanation:
Antoine-Laurent de Lavoisier, also Antoine Lavoisier after the French Revolution, was a French nobleman and chemist who was central to the 18th-century chemical revolution and who had a large influence on both the history of chemistry and the history of biology.
Which of the cells shown is a prokaryote?
A) muscle cell B) nerve cell C) bacterium D) red blood cell
A block of material has a density of 1.29 g/cm. what is the volume of 190 g in cubic
centimeters?
No units required
Answer:
147.28 cm³
Explanation:
Density = m/V
1.29 g = 190 g/cm3/V
V = 190 g/cm³ : 1.29 g
V = 147.28 cm³
Which metalloid has five valence electrons in the fourth electron shell?
antimony
germanium
selenium
arsenic
Answer:
A- antimony
Explanation:
Answer:
A
Explanation:
What is the main process that happens in the mantle?
Answer:
Mantle convection is the very slow creeping motion of Earth's solid silicate mantle caused by convection currents carrying heat from the interior to the planet's surface. The Earth's surface lithosphere rides atop the asthenosphere and the two form the components of the upper mantle.
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what is the molar mass of dimethylglyoxime, c4h8n2o2?
Explanation:
The molar mass of a compound can be calculated by finding the molar of the individual atoms that combine to make the compound.
Molar mass of compound =
∑ (molar mass of element × number of atoms of the element)
∴ Molar mass of dimethylglyoxime
= 4C + 8H + 2N + 2O
= [(4 × 12.011) + (8 × 1.0080) + (2 × 14.007) + (2 × 15.999)] g/mol
= 116.12 g/mol
∴ the molar mass of dimethylglyoxime = 116.12 g/molStudying the brightness of a star can help scientist determine what part of the life-cycle a star is in. Is this true or false
Answer:
what do you mean?
Explanation:
Studying the brightness of a star can indeed help scientists determine what part of the life-cycle a star is in. The brightness of a star is directly related to its stage in the life cycle.The statement is true.
During the early stages of a star's life, it is formed from a cloud of gas and dust. As the star contracts under its own gravity, it starts to heat up and emits light. This is known as the protostar stage.
As the star continues to contract, it reaches a point where the core temperature becomes hot enough for nuclear fusion to occur. At this stage, the star enters the main sequence phase, where it will spend the majority of its life. The brightness of the star in this phase is determined by its mass. More massive stars are brighter than less massive ones.
As the star ages, it exhausts its hydrogen fuel in the core and begins to evolve. Depending on its mass, a star can become a red giant, a white dwarf, a neutron star, or even a black hole. Each of these stages has a different brightness profile.
By observing the brightness of a star over time, scientists can gather information about its age, mass, and evolutionary stage. This can provide insights into the star's life cycle and help in understanding the processes occurring within it.
Thus, studying the brightness of a star is an important tool for scientists to determine what part of the life cycle a star is in. By analyzing its brightness profile, scientists can gain valuable information about the star's age, mass, and evolutionary stage.The statement is true.
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Elements in the same period have the same…
Answer:
Elements in the same period have the same (number of electron shells)
1. A sample of nitrogen occupies a volume of 250 mL
at 298 K. What volume will it occupy at 268 K?
Answer:
0.225 L = 225 mL
Explanation:
Charles' Law states that for a fixed pressure, the volume is directly proportional to the temperature, which means things expand at the same rate as the rate of it being heated up
Mathematically, we can write that as:
V1/T1 = V2/T2, where 1 and 2 are the two situations
So, when we substitute the values in, we get:
0.25 L/298 K = V2/268 K
Rearranging this, we get:
(0.25/298) x 268 = 0.225 L = 225 mL.
This also makes sense, as the volume reduced a little when the temperature reduced (cooled down)
Let me know if this makes sense, and hope I helped! :)
3. How does
photosynthesis affect
your daily life?
Answer:
to create oxygen and energy in the form of sugar
Explanation:
photosynthesis is the process by which plants use sunlight, water, and carbon dioxide
How much heat is needed to raise a 0.30 g piece of aluminum from 30.C to 150C? The specific heat of aluminum 0.900j/gC
Answer:
hi
Explanation:
the variable part of an amino acid is the __________.
answer: the variable part of an amino acid is the: SIDE CHAIN
what are the conditions from our notes that affect natural Selection?
Answer:
Conditions that affect natural selection are reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population. If they are met, natural selection automatically results.