Answer:
Tanzanite
Explanation:
Tanzanite is the exquisite blue-purple variety of the mineral zoisite that is only found in one part of the world. Named for its limited geographic origin in Tanzania, tanzanite has quickly risen to popularity since its relatively recent discovery.
Which of the following would tell you that a weak base is present?
A. An indicator added to the solution turns green-blue.
B. If there is a high reaction rate.
C. If the pH of the solution is close to 14.
D. If the solution is a good conductor of electricity.
Answer:
A. An indicator added to the solution turns green-blue.
Explanation:
A pH scale measures the concentration of hydrogen ions in acidic and alkaline solutions.
In chemistry, pH literally means the power of hydrogen ions and it is a measure of the molar concentration of hydrogen ions in a particular solution; thus, specifying the acidity, neutrality or basicity of any chemical solution.
Mathematically, the pH of a solution is given by the formula;
[tex] pH = -log_{10}(H^{+}) [/tex]
On a pH scale, a solution with a pH of 7 is neutral, a solution with a pH below 7 is acidic and it's basic (alkaline) when it's pH is above 7.
A pH indicator can be defined as a compound (substance) that indicates the concentration of hydrogen ions present in a solution by changing its color over a narrow range of pH values.
A pH range of 1 to 3 (1 - 3) represents a strong acid with a red color.
When an indicator added to a solution turns green-blue, it simply means that a weak base is present.
What is the energy of a photon emitted with a wavelength of 448 nm?
O A. 2.97 x 10-22 J
O B. 4.44 x 10-19 J
O C. 8.91 x
10-23 J
O D. 1.48 x 10-27 J
Answer: B is the correct answer
Explanation:
The energy of a photon is 4.44×[tex]10^{-19}[/tex]J for the wavelength of 448 nm.
So, option (B) is correct. This can be calculated by using the energy formula.
The energy of a photon:The energy of a photon is said to be photon energy. It is directly proportional to the photon's electromagnetic frequency and inversely proportional to the wavelength. If the frequency of the photon is high then its energy is also high.
The energy of a photon, E=hc/λ
Given data:Given that,
λ = 448nm
h= 6.63×[tex]10^{-34}[/tex]J/s
Calculating the energy:E = 6.63×[tex]10^{-34}[/tex]×3×[tex]10^8[/tex]/448×[tex]10^-^9[/tex]
E = 4.44×[tex]10^{-19}[/tex] J
Hence option (B) is correct.
Therefore, the energy of a photon emitted with a wavelength of 448nm is 4.44×[tex]10^{-19}[/tex] J.
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Write down the constituent elements present in the following compounds.
a. Sodium Sulphate
b. Baking Soda
c. Limestone
d. Bleaching powder
e. Ammonia
f. Caustic Soda
g. Glucose
h. Ammonium Carbonate
I. Acetic acid
j. sulphuric acid
Answer:
in sodium sulphate there is sodium an sulphur
A toaster has a resistance of 28 Ω and is plugged into a 110 V circuit. Using the GRASS method, what current is measured?
Answer:
The current of the toaster is 3.93A
Explanation:
Using the GRASS method:
G: Given: The information that is given is that we have 28Ω of Resistance and 110V of voltage.
R: Required: We need to find the current measured.
A: Action: We can use Ohm's law that relates resistance, voltage and current in the equation:
V = R*I
Or:
I = V/R
Where I is current in A, V is voltage = 110V and R is resistance = 28Ω
S: Solve:
I = 110V / 28Ω
I = 3.93A
S: Statement:
The current of the toaster is 3.93AWhich compound in 1 mol/dm3 solution has the highest PH value? a) Ethanoic acid b) Sodium chloride c) Sodium hydroxide d) Hydrogen chloride
Answer:
Explanation:
A. Ethanoic acid-acetic acid being weak acid dissocated weekly and turns solution to weakly acidic, ph will be between 4-7,
B. Hydrochloric acid - the solution would be acidic- with lots of H+ ions, Ph will be between 1-4,
C. Sodium chloride - solution prodcued netural Na+ and Cl- hence wont affect ph of solution will be equalt to 7.
D. Sodium hydrogen carbonate-NaHCO3 is weak base and the PH will be above 7,
An aqueous solution contains
32.7% KCl (weight/weight %).
How many grams of water (H20) are contained in 100 g of this solution?
Answer:
67.3g
Explanation:
%(w/w) = mass of solute/total mass of solution × 100
According to this question, an aqueous solution contains 32.7% KCl (w/w%). Firstly, we find the mass of the solute (KCl) as follows, if the mass of solution is 100g:
32.7 = mass of solute/100 × 100
mass of solute (KCl) = 32.7g
Mass of solution = mass of solvent (water) + mass of solute (KCl)
100g = x + 32.7g
x = 100 - 32.7
x = 67.3
Hence, the mass of water contained in the 100g solution is 67.3g.
What is the chemical formula of Sulphuric Acid:-
Answer:
sulphuric acid's formula is H²SO⁴
Explanation:
HOPE U WILL FOLLOW
The atomic number of silicon (Si) is 14. What's the electron configuration for silicon? Question 1 options:
A) [Ar] 3p5
B) [He] 1s2 2p6
C) [Ne] 3s2 3p2
D) [He] 2s2 3p2
Answer:
D.[Ne] 3S2 3P2
Explanation:
The electron configuration for silicon is [Ne] 3s² 3p². Hence Option (C) is correct.
What is elctronic configuration ?Electronic configuration, also called electronic structure or electron configuration, the arrangement of electrons in orbitals around an atomic nucleus.
The electron configuration of an element describes how electrons are distributed in its atomic orbitals.
Electron configurations of atoms follow a standard notation in which all electron-containing atomic subshells (with the number of electrons they hold written in superscript) are placed in a sequence.
Silicon belongs to group 14th and 3rd period.Therefore, The electron configuration for silicon is [Ne] 3s² 3p². Hence Option (C) is correct.
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what is electrolysis
Answer:
Electrolysis is commercially important as a stage in the separation of elements from naturally occurring sources such as ores using an electrolytic cell
If 56 grams of carbon monoxide burns in oxygen to produce 88 grams of carbon dioxide, the mass of oxygen involved in the reaction is
grams.
The answer is 32 grams!
hope I helped
Is lithium (Li) more or less reactive than beryllium (Be)? Why?
Answer:
Below!
Explanation:
Lithium (Li) is more reactive than Beryllium (Be). This is because Lithium lacks the valence electron that Beryllium has. Elements with a lower amount of valence electrons are less stable than those with full valence shells, causing it to react more easily. Because Lithium only contains 1 valence electron, it is easily transferred/given up to create bonds and form compounds.
Hope this helps ya! Best of luck <3
Compared to beryllium, lithium (Li) is much more reactive (Be). This is due to Lithium's lack of Beryllium's valence electron.
What is chemical reactivity?Reactivity in chemistry is a gauge of the ease with which a substance reacts chemically. The chemical may react independently or in combination with other atoms and compounds, and in either case, energy will typically be released. The most reactive substances and elements have the potential to spontaneously or explosively ignite.
They typically ignite when exposed to oxygen in the atmosphere and water. Reactivity is temperature-dependent. The available energy for just a chemical reaction increases with temperature, often increasing its likelihood. The noble gases are the least reactive elements. Hydrogen is the least active catalyst in this group and doesn't produce any stable compounds. Compared to beryllium, lithium (Li) is much more reactive (Be). This is due to Lithium's lack of Beryllium's valence electron.
Therefore, compared to beryllium, lithium (Li) is much more reactive (Be). This is due to Lithium's lack of Beryllium's valence electron.
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PLZ HELP which ia an example of a scientist using a physical model to describe a river
A. the scientists thinks of a river like a flow of electrons
B. the scientists builds a model of the river using plastic and a hose
C. the scientists writes an equation that describes the flooding of the river
D. the scientists uses a computer to predict how much water will flow
functions of idiophones
is any musical instrument that creates sound primarily by the vibration of the instrument itself without the use of air flow
Question 22 of 30
What is the balanced form of the chemical equation shown below?
C6H1206(s) + O2(g) → H2O(l) + CO2(9)
A. CH 0(s) + O2(g) → H2O(1) + CO2(g)
B. CoH1206(s) + O2(g) → 12H2O(l) + 6CO2(g)
C. C6H1206(s) + O2(g) → H20(1) + CO2(g)
D. CoH 206(s) + 602(g) → 6H2O(l) + 6CO2(g)
SU
Answer:
C6H12O6+6O2--->6CO2+6H2O
Explanation:
So I went through all the answers and could not find the right one amongst. If I'm not wrong the reaction above is the reaction for respiration. The nearest answer is D but unfortunately the first reactant isn't in accordance with that which the question has given.
What does it mean to view something from a frame reference
Answer:
In physics, a frame of reference, or reference frame, is a perspective that one uses to determine if an object is moving.
For example, when you see a ball roll down a street, you can tell the ball is moving because the frame of reference is the streets, whatever may be on the side of the roads, or the Earth
If 16.4 grams of calcium nitrate is heated as shown in the reaction:
2Ca(NO3)2 -> 2CaO + 4NO2 + O2.
Calculate the volume of nitrogen dioxide produced at STP.
Answer:
7.2
Explanation:
you first have to find the number of moles of nitrogen dioxide by using the number of moles for calcium nitrate and the mole to mole ratios
number of moles of calcium nitrate=mass/mm
=16.4/102
=0.16g/mol
then you use the mole to mole ratios
2 : 4
0.16: x
2x/2=0.64/2
x=0.32g/moles of nitrogen dioxide
then you use the formula for the volume
v=22.4n
=22.4×0.32
=7.2
I hope this helps
Infrared waves are an example of heat transfer by
A. convection
B. radiation
C. conduction
D. motion of the air
Answer:
convection is my correct answer
What unusual physical property does liquid sulfur exhibit from about 113∘C to 230∘C? Select the correct answer below: A. Its vapor pressure decreases with increasing temperature. B. Its vapor pressure increases with increasing temperature. C. Its viscosity decreases with increasing temperature. D. Its viscosity increases with increasing temperature.
Answer:
C. Its viscosity decreases with increasing temperature
Explanation:
The liquid Sulphur is a liquid that turs yellowish green. At a temperature of 120 it tends to melt and has a lower viscosity.Hurry PLEASEEE
How many grams are 1.20 x 10^°25molecules of
calcium iodide?
Please show work!:)
A student wants to separate a mixture of salt and water in a laboratory (a) Describe how the student can obtain both salt and water from the salt solution
Answer:
okay so basically what you are being tested is if you know the difference between simple and fractional distillation and okay you can evaporate the mixture but you won't obtain water so you will use simple distillation to obtain both salt and water
Which of the following materials contains a base?
a. Stomach digestive juices
b. Orange juice
c. Ammonia window cleaner
d. Vinegar
Answer:
c. ammonia window cleaner
Explanation:
Window cleaners contain ammonia (a base) for the purpose of removing the dust and grease on the windows.
digestive juices, orange(a citrus) juice, and vinegar are all highly acidic.
... give me brainliest please :)) ...
When under a pressure of 9.5 atm, a piston has a volume of 1.7 liters. It the piston is compressed to a
volume of 1.1 liters, what will the new pressure be?
c. 8.90 atm
a. 5.08 atm
b. 6.15 atm
d. 14.7 atm
Answer:
D
Explanation:
according to boyle's law the temperature and pressure of a gas are inversely proportional given by the equation
p1v1=p2v2
In this case p1 is 9.5,v1 is 1.7,v2 is 1.1 and we have to find p2
9.5×1.7=p2×1.1
16.15/11=1.1p2/1.2
p2=14.7
I hope this helps
Answer:
[tex]\boxed {\boxed {\sf D.\ 14.7 \ atm}}[/tex]
Explanation:
We are asked to find the pressure on a gas given a change in volume. We will use Boyle's Law which states the volume of a gas is inversely proportional to the pressure. The formula for this law is:
[tex]P_1V_1=P_2V_2[/tex]
The gas originally has a pressure of 9.5 atmospheres and a volume of 1.7 liters.
[tex]9.5 \ atm * 1.7 \ L = P_2V_2[/tex]
The gas is compressed to a volume of 1.1 liters, but the pressure is unknown.
[tex]9.5 \ atm * 1.7 \ L = P_2* 1.1 \ L[/tex]
We want to find the new pressure, so we must isolate the variable P₂. It is being multiplied by 1.1 liters. The inverse operation of multiplication is division. Divide both sides of the equation by 1.1 L.
[tex]\frac {9.5 \ atm * 1.7 \ L}{1.1 \ L} =\frac{ P_2* 1.1 \ L}{1.1 \ L}[/tex]
[tex]\frac {9.5 \ atm * 1.7 \ L}{1.1 \ L} =P_2[/tex]
The units of liters cancel.
[tex]\frac {9.5 \ atm * 1.7 }{1.1 } =P_2[/tex]
[tex]\frac {16.15}{1.1} \ atm =P_2[/tex]
[tex]14.6818181818 \ atm= P_2[/tex]
Round to the tenths place. The 8 in the hundredth place tells us to round the 6 up to a 7.
[tex]14.7 \ atm \approx P_2[/tex]
The new pressure at a volume of 1.1 liters is approximately 14.7 atmospheres.
Potassium impart purple colour but beryllium do not impart any colour to the flame.Why?
Answer:
The electrons in beryllium and magnesium are too strongly bound to get excited by flame. Hence, these elements do not impart any color.How many moles are in 68 liters of H2S gas at STP? :}
Answe:
Explanation:
số mol của H2S là : 68/22.4=3.03 nha
please answer this questions soon
i will mark him or her brillient
Answer:
1)Or
d.Sublimation
2)
b.iodine is the solute and alcohol is solvent
3)
a.compostion of solute
Answer:
1) a) centrifugation
OR
b) sublimation
2) a) iodine is the solute and alcohol is solvent
3) a) concentration of soLute
A gas occupies 210 mL at -73°C to have the same gas occupy 360 mL:
should the temperature be increased or decreased?
what is the new temperature? __ K
Answer:
a. The temperature should be increased.
b. 342.86K
Explanation:
Using Charles law equation as follows:
V1/T1 = V2/T2
Where;
V1 = initial volume (mL)
V2 = final volume (mL)
T1 = initial temperature (K)
T2 = final temperature (K)
According to this question, the following information were given:
V1 = 210mL
V2 = 360mL
T1 = -73°C (-73 + 273 = 200K)
T2 = ?
Using V1/T1 = V2/T2
210/200 = 360/T2
Cross multiply
200 × 360 = 210 × T2
72000 = 210T2
T2 = 72000/210
T2 (new temperature) = 342.86K
Which part of a cell directs the cell's activities and holds its DNA?
A. Mitochondrion
B. Ribosome
C. Nucleus
D. Cell membrane
Answer:
Nucleus is the answer
A micrograph of animal cells, showing the nucleus (stained dark red) of each cell. Known as the cell's “command center,” the nucleus is a large organelle that stores the cell's DNA (deoxyribonucleic
Answer:
nucleus is the part of a cell directs the cells Activities and holds it's DNA
balance chemical reaction of oxalic acid with conc. sulphuric acid
Answer:
Explanation: since oxalic acid is a weak acid it wont provide a strong acidic medium. So in order to provide a strong acidic medium dilute sulphuric acid is added.
balance the equation:2Na+3H2O-2NaOH+H2
Answer:
2Na + 2H2O → 2NaOH + H2
Explanation:
A balanced equation is an equation for a chemical reaction in which the number of atoms for each element in the reaction and the total charge are the same for both the reactants and the products.
What is the quantity of carbon-14 in a bone after 17,190 years if the initial mass of C-14 is 0.300 grams and the half-life is 5,730 years?
A.
0.038 g
B.
0.093 g
C.
0.281 g
D.
0.412 g
A. 0.038 g.
Explanation:
The decay of carbon-14 is a first order reaction.
The rate constant of the reaction (k) in a first order reaction = ln (2)/half-life = 0.693/(5730 year) = 1.21 x 10⁻⁴ year⁻¹.
The integration law of a first order reaction is:
kt = ln [Ao]/[A]
k is the rate constant = 1.21 x 10⁻⁴ year⁻¹.
t is the time = 17,190 years.
[Ao] is the initial concentration of carbon-14 = 0.300 g.
[A] is the remaining concentration of carbon-14 = ??? g.
∵ kt = ln [Ao]/[A]
∴ (1.21 x 10⁻⁴ year⁻¹)(17,190 years) = ln (0.300 g)/[A]
2.08 = ln (0.300 g)/[A]
Taking exponential for both sides:
8.0 = (0.300 g)/[A]
∴ [A] = 0.0375 g ≅ 0.038 g
