Calcium oxide + water = calcium hydroxide.
Magnesium + hydrochloric acid = magnesium chloride + hydrogen.
Sodium hydrogen carbonate + citric acid = Na3C6H5O7(aq)+3H2O(l)+3CO2(g)
Iron + salt water = 4Fe(OH)3 (rust)
Answer:
1. CaO + H2O _____ Ca(OH)2
Calcium oxide + Water _____ Calcium hydroxide
2. 2 HCI + MG _____ MgCl2 + H2
Magnesium + hydrochloric acid _____ Magnesium Chloride + hydrogen gas
The half-life of a radioactive substance is 15 days. After 10 days a sample of the substance has been reduced to a mass of 4 mg. A. What was the inital mass (in mg) of the sample? B. Using your answer from above, after how many days will there only be 0. 3 mg of substance left?.
A. The initial mass of the sample is 6.35
B. The time taken for 0.3 mg of the sample to remain is 66 days
A. Determination of the initial mass of the sample
We'll begin by calculating the number of half-lives that has elapsedHalf-life (t½) = 15 days
Time (t) = 10 days
Number of half-lives (n) =?n = t / t½
n = 10 / 15
n = ⅔Finally, we shall determine the initial mass of the sample.Number of half-lives (n) = ⅔
Amount remaining (N) = 4 mg
Initial amount (N₀) =?[tex]N_0 = N \times {2}^{n} \\ N_0 = 4 \times {2}^{2 \div 3} \\ N_0 = 6.35 \: mg[/tex]
Therefore, the initial mass of the sample is 6.35 mg
B. Determination of the time
We'll begin by calculating the number of half-lives that has elapsedAmount remaining (N) = 0.3 mg
Initial amount (N₀) = 6.35 mg
Number of half-lives (n) =?[tex]{2}^{n} = \frac{N_0}{N} \\ \\ {2}^{n} = \frac{6.35}{0.3} \\ \\ {2}^{n} = 21.167 \\ take \: the \: log \: of \: both \: side \\ log \: {2}^{n} = log \: 21.167 \\ nlog2 = log \: 21.167 \\ divide \: both \: side \: by \: log2 \\ \\ n = \frac{log \: 21.167}{log2} \\ \\ n = 4.4[/tex]
Finally, we shall determine the timeNumber of half-lives (n) = 4.4
Half-life (t½) = 15 days
Time(t) =?t = n × t½
t = 4.4 × 15
t = 66 daysTherefore, it will take 66 days for 0.3 mg of the sample to remain.
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(Help me out )
When a single electron returns to the ground state from an excited state, it emits___
1. A continuous spectrum of all wavelengths of light
2. A line spectrum of 2 or more wavelength of light
3. A single, specific wavelength of light
4. No light
Answer:
3) A single specific wavelength
Explanation:
When an electron returns to ground state, it has to emit a single photon.
When a single electron returns to the ground state from an excited state, it emits a single, specific wavelength of light. Therefore, option 3 is correct.
What is wavelength ?The separation between any two points in a wave and those identical points in the following wave cycle. This can be null-to-null, crest-to-crest, trough-to-trough, etc.
A spectrum is the term used to describe the range of wavelengths or frequencies for wave phenomena. The term was originally used to describe the electromagnetic spectrum, but it is now used to describe the sound spectrum and vibration spectrum.
When electromagnetic radiation such as radio waves, light waves, or infrared waves travel across space, they leave behind distinctive patterns. Each wave has a distinct size and form. Wavelength is the separation between peaks.
Thus, option 3 is correct.
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Unlike solids and liquids, gases can be compressed. How is this physical characteristic of gases beneficial to society?
asap help for brainlist
Which pair of atoms will form a covalent bond?
Question 7 options:
H and O
Li and I
K and Fl
Na and Cl
Answer:
h and o
Explanation:
because both are non metals
How can you classify matter?
Answer:
Matter can be broken down into two categories: pure substances and mixtures. Pure substances are further broken down into elements and compounds. Mixtures are physically combined structures that can be separated into their original components. A chemical substance is composed of one type of atom or molecule.
Hope this helps :)
Which of the following element has more than one valence number. A.gold,b.iron,c.silver,d.aluminum
Answer:
iron
iron has +2 valancy
Answer:
C silver
Explanation:
silver have high quantity load that passes through magnesium towards overload despised everything happens through magnetic century.
Consider the Sy2 reaction between 1-bromo-2-methylpropane and methoxide. Add curved arrows to the starting materials to
indicate the flow of electrons. Draw the product species to show the balanced equation, including nonbonding electrons and
formal charges.
H2
Н.С.
Br:
-CH3
product
n Shot
07.42 PI
H
+
CH3
n Shot
.07.13 P1
Draw curved arrows.
Draw the products. The bromide ion has been drawn
for you.
Draw
Select
Rings
More
Erase
Question"
Select
Draw
Rings
More
Erase
h Shot
10.36 PI
///
С
Br
O
С
Br
o
n Shot
-2
Answer:
sdfs
Explanation:
dfssdf
When 1-bromo-2-methylpropane is reacted with methoxide the same product 1-methylprop-2-ene is obtained. This reaction is attached in image below:
What is SN₂ reaction ?The SN2 reaction is a nucleophilic substitution reaction that breaks one bond while forming another. The rate-determining step of the reaction involves two reacting species. SN2 is an abbreviation for Substitution Nucleophilic Bimolecular.
The reaction is bimolecular because two molecules are present in the transition state, as indicated by the number 2 in the SN2 symbol. As a result, the rate of the reaction is affected by the concentrations of both the nucleophile and the substrate.
The SN2 reaction is a nucleophilic substitution with two components in the rate determining step. -SN2 reactions are bimolecular, with bond-forming and bond-breaking steps occurring simultaneously. There is no intermediate in -SN2 reactions.
Thus, product 1-methylprop-2-ene is obtained.
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what is the best way to study and understand electron configuration??
Answer:
You have to remember this memory aid, diagonals and all.
You have to keep a tight tally of the electrons you’ve used so far so you don’t go over the number of electrons in the element you’re working on.
You have to remember how many electrons fit into each subshell (s, p, d, f).
It takes a lot of time, especially when the element has more than 20 electrons.
Explanation:
methane is called an organic compound why
Answer:
Explanation:
1) Organic compounds always contain only p-block elements (Groups III-VII), at least one of which must be carbon. 2) Organic compounds almost always contain one or more C-H bonds. ... Thus, all bonds are typically covalent in organic compounds. Methane (CH4) is the prototypical organic molecule.
Methane contains carbon, forming covalent bonds, and is found in living organisms, making it an organic compound.
Methane (CH₄) is considered an organic compound due to its molecular structure and occurrence in living organisms. Organic compounds are primarily composed of carbon atoms covalently bonded to hydrogen and often other elements like oxygen, nitrogen, sulfur, and more.
Methane consists of one carbon atom bonded to four hydrogen atoms through covalent bonds. Carbon's unique ability to form stable covalent bonds with other elements, including itself, leads to the vast diversity of organic molecules found in living organisms.
Methane is a crucial component of natural gas and is produced by various biological and geological processes. It is present in the digestive systems of animals, formed during decomposition, and plays a role in carbon and energy cycles.
Its prevalence in living systems and its molecular structure classify methane as an organic compound, reflecting the foundational principles of organic chemistry.
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The complete question is :
Methane is called an organic compound why?
How many grams of acetic acid are present in 250g of vinegar that contains 5.00% acetic acid?
Four preparations involving table sugar (sucrose) are described below. Analyze the sugar preparation processes and the end products.
Sugar Water Sugar Floss Sugar Caramel Rock Sugar
Sugar is added to water, and the water is stirred until the sugar is no longer visible. Sugar is melted and blown with a fan to make thin threads of solid sugar. Pure sugar is melted and cooked until it changes color and becomes a thick, sticky liquid. A highly concentrated solution of sugar water is prepared, large sugar crystals are allowed to form slowly, and then dye is added.
Which of the following is evidence that a chemical reaction has taken place in one of the processes?
A.
the melting and re-solidification of sugar into threads, which are different from sugar’s natural cube-shaped crystals
B.
the slow growth of giant sugar crystals from a highly concentrated sugar-water solution and added dye
C.
the dissolution of solid sugar in water to form a thin, colorless, odorless liquid
D.
the color change that takes place after heat melts and begins to decompose the sugar
Answer:
b
Explanation:
Answer: d:the color change that takes place after heat melts and begins to decompose the sugar
Explanation:i did the study island
A yellow solid, W is soluble in water. Which method of separation can be used to obtain the solid W from an aqueous solution?
A Neutralisation
B Chromatography
С Distillation
D Crystallisation
Count the atoms in 717 grams of Nitrogen.
Answer:
3.08x10^25
Explanation:
Divide the mass in grams by the molar mass of nitrogen (14.0067), then multiply the result by Avogadro's number (6.022x10^23). Then round to the correct amount of significant figures.
What type of reaction is shown below? Check all that apply. 2Na Cl2 → 2NaCl synthesis decomposition combustion.
Answer:
Synthesis
Explanation:
Trust me on this :)
what is an environmental result from burning fossil fuels?
Answer:
Burning fossil fuels emits a number of air pollutants that are harmful to both the environment and public health. Sulfur dioxide (SO2) emissions ...
what is the difference in chemical energy between organic and inorganic materials?
Answer:
the difference is the presence of a carbon atom
Explanation:
The equation for the reaction between magnesium and hydrogen is written below
mg+2hcl------mgcl (2)+H (2)
(1) what mass of magnesium would be needed to give 50g of hydrogen? (mg=24, H=1)
(2) what volume would this gas occupy at s.t.p
Answer:
Explanation:
The balanced equation says that we'll get 1 mole of H2 for every 1 mole of Mg. 50 grams of H is 50g/2 g/mole = 25 moles of H2. That means we'll need 25 moles of Mg. Convert that into grams: (25 moles Mg)*(24.3 g/mole) = 607 grams Mg.
At STP, all gases occupy 22.4 liters/miole. That means 25 moles of H2 would occupy (25 moles)*(22.4 liters/mole) = 560 liters.
The _______________ emits radiant energy toward Earth’s surface
Answer:
The Sun is your answer.
Explanation:
it is.
Two chemical reactions are shown:
A. Ca(OH)2 - CaO + H2O
B. 4K + O2 + 2K20
Which statement is true?
A. Both are synthesis reactions
B. Both are decomposition reactions
C. A is a synthesis reaction, and B is a decomposition reaction
D. A is a decomposition reaction, and B is a synthesis reaction
Answer: A is a decomposition reaction, and B is a synthesis reaction
Explanation: the first equation shows the reactant breaking up into 2 parts aka decomposition and equation 2 shows the reaction being combined into one part, aka synthesis. hope that helps!
Answer:
Answer d
Explanation:
when the corporation issuing the bonds has the right to redeem the bonds prior to the maturity, the bonds are
Answer:
Callable or redeemable bonds
Explanation:
"..are bonds that can be redeemed or paid off by the issuer prior to the bonds' maturity date."
Explain why some metals are extracted by heating their oxides with carbon, but some metals cannot be extracted in this way
Answer:
This happens because a metal is less reactive than carbon and it can be extracted from its oxides by heating with carbon. The carbon displaces metal from the compound and removes the oxygen from the oxide.
elements in the second group are also very reactive. they are called:
Answer:
Explanation:
IIA elements in the periodic table are the alkali earth metals
PLS HELP! I’m marking brainliest as well
How many atoms exist in 100.0 grams of lithium
why the mixture of bromine and ethane is discoloured when left in the sun
Answer:
In the presence of UV light, ethane will react with bromine in a substitution reaction. UV light is the condition under which the reaction will occur so it is written above the arrow in the chemical equation. As the reaction proceeds, the intensity of the re-brown colour of the bromine water decreases.
Answer:
here ya go
Explanation:
combining bromine and ethane leads to a brown gas or liquid which is made of the elements. it is a gas at room temperature and does not affect human beings. there are many uses for bromine compounds but they are mainly used for the manufacturing of chlorine, fire retadants, water purification, graphy chemicals and pharmaceutcals. it is a naturally occurring element that can be found in animals such as sharks since they produce their own.
Valence electrons are electrons in the ? of an atom.
Answer:
Valence electrons are the outermost of electrons.
Explanation:
valence electrons are the outermost electrons of an atom located in the shell/ orbit
Which factor most often affects wind and weather patterns on Earth?
Answer:
i think its solar radiation
What is the frequency of yellow light, which has a wavelength of 5.56 x 10^-7 m?
O A) 5.40 x 10^14 m/s
O B) 5.40 x 10^14 Hz
O C) 1.85 x 10^15 m/s
O D) 1.85 x 10^15 Hz
The frequency of yellow light, which has a wavelength of 5.56 x 10^-7 m is 5.40 x 10^14 Hz. Therefore, option B is correct.
What do you mean by wavelength ?The distance between identical points (adjacent crests) in adjacent cycles of a waveform signal propagated in space or along a wire is defined as the wavelength. This length is typically specified in wireless systems in meters (m), centimeters (cm), or millimeters (mm) (mm).
The wavelength is the distance between two wave crests, and it is also the distance between two wave troughs. The frequency is measured in cycles per second (Hz) and is the number of vibrations that pass over a given spot in one second (Hertz).
Speed is distance over time, Therefore, v = λ / T.
The frequency, f, is 1/T, so the equation relating wave speed, frequency, and wavelength is v = c / λ .
Given :
Wavelength = 5.56 x 10^-7 m
Frequency = ?
Speed (c) = 3 × 10⁸m/s
v = c / λ
By substituting given values in equation and we get,
v = 3 × 10⁸ / 5.56 x 10^-7
= 5.40 x 10^14
The frequency of yellow light is 5.40 x 10^14.
Thus, option B is correct.
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What is the density of an object that has a mass of 149. 8 g and displaces 12. 1 ml of water when placed in a graduated cylinder?.
Answer:
12.38 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]d = \frac{m}{v} \\ [/tex]
m is the mass
v is the volume
From the question
m = 149.8 g
v = 12.1 mL
We have
[tex]d = \frac{149.8}{12.1} = 12.380165... \\ [/tex]
We have the final answer as
12.38 g/mLHope this helps you
Question 2
20 pts
What types of elements make up salt and what type of compound is it?
nonmetals only and covalent
metals only and ionic
metals and nonmetals and ionic