The question is incomplete, the complete question is;
The half-life of strontium-90 is about 29 years. How many half-lives have elapsed when 6.25% of a strontium- 90 sample remains in the container?
Answer:
4 half lives
Explanation:
From;
N/No = (1/2)^t/t1/2
N= amount of strontium-90 present at time t
No= amount of strontium-90 originally present
t= time taken
t1/2 = half life of strontium-90
But N= 0.0625No
Hence;
0.0625No/No = (1/2)^t/29
0.0625 = (1/2)^t/29
(1/2)^4 = (1/2)^t/29
4 = t/29
t = 4 × 29
t= 116 years
Hence four half lives have elapsed
The pH of a solution with a [OH-] of 1x10^-6 is
Answer:
pH = 6
Explanation:
Given that,
The concentration of [OH]⁻ ion is [tex]10^{-6}[/tex].
We need to find the pH of the solution.
We know that,
[tex]pH=-\log[OH]^-[/tex]
Put all the values,
[tex]pH=-\log(10^{-6})\\\\pH=6[/tex]
Hence, the pH of the solution is 6.
Use the periodic table to determine the amount of copper and aluminum nitrate formed in the reaction.
Type the correct answer in the box. Express your answer to the correct number of significant figures.
In the reaction,
moles of Cu and
moles of Al(NO3)3 are formed.
Answer:
23, 51
Explanation:
Edmentum/plato
As per the balanced reaction, 2 moles of aluminum metal and 3 moles of copper nitrate gives 2 moles of aluminum nitrate and 3 moles of copper metal. 10 g of Al and 25g of copper nitrate gives 0.08 moles of aluminum nitrate and 0.13 moles of copper.
What is limiting reactant ?A limiting reactant is the reacting species which is not sufficient in amount to complete the reaction. Hence, the limiting reactant determines the yield of the reaction.
The given reaction is written as:
[tex]\rm 3Cu(NO_{3})_{2} + 2Al \rightarrow 2 Al(NO_{3})_{3} + 3Cu[/tex]
2 moles of Al and 3 moles of copper nitrate gives 2 moles of aluminum nitrate and 3 moles of Cu.
Molar mass of copper nitrate = 187.5 g/mol
atomic mass of aluminum = 27 g/mol
then, number of moles in 10 g of Al = 10 g/27 g/mol = 0.37 moles.
number of moles in 25 g of copper nitrate = 25 g/187.5 g/mol = 0.13 moles.
0.37 moles of Al needs 0.5 moles of copper nitrate to react with. Hence, copper nitrate is the limiting reactant.
3 moles of copper nitrate gives 2 moles of aluminum nitrate. Then 0.13 moles will give 2/3rd of 0.13 i e., 0.08 moles of aluminum nitrate. Similarly 0.13 moles copper nitrate gives 0.13 moles of copper metal.
Find more on limiting reactant:
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Your question is incomplete. But your complete question probably was:
10 g of aluminum metal reacts with 25 g of copper nitrate. Use the periodic table to determine the amount of copper and aluminum nitrate formed in the reaction.
In the reaction,
moles of Cu and
moles of Al(NO3)3 are formed.
The word habitable is defined as:
The part of an atom that has an overall positive charge is called
A)
an electron
B)
the nucleus
C)
the first shell
D)
the valence shell
Answer: I think it’s B
A certain element has two naturally occurring isotopes. The atomic mass of isotope 1 (35.4723 % natural abundance) is 184.9529 amu. Determine the atomic mass of isotope 2. The average atomic mass of the element is 186.2071 amu. Do not include units; report answer to 4 decimal places.
Answer:
the value
Explanation:
Calculate the molarity of the following solution: 1.0 mole of KCl in .75 L of solution.
1.3 M
2.0 M
0.750 M
99 M
Answer:
1.3 M
Explanation:
1 mole= Concentration * Volume
1 mole=C*0.75 L
C=1.3 M
A wheelbarrow can be used to help lift a load, such as a pile of dirt, and then push the load across a distance.
A man pushes a wheelbarrow.
Which simple machines make up a wheelbarrow?
a pulley and an inclined plane
a wheel and axle and a lever
a pulley and a wheel and axle
a lever and a wedge
Answer: it consists of two simple machines: a lever and a wheel and axle. Effort is applied to the lever by picking up the handles of the wheelbarrow.
Explanation:
Answer:
B
Explanation:
B)
Use the reaction N2(g) + 3H2(g) 2NH3(g) to answer the following questions
a. 1 pt: What does Le Châtelier's principle predict would happen to the equilibrium conditions if N2(g) + 3H2(g) were added to the system?
b. 1 pt: What would happen to the equilibrium if the pressure were decreased?
c. 2 pts: Write the equation for calculating Keq
d. 3 pts: Calculate the value for Keq given the following concentrations
[NH3] = 6 M
[H2] = 4 M
[N2] = 3 M
Answer:
cvbn
Explanation:
A set of charged plates is
separated by 8.08*10^-5 m. When
2.24*10^-9 C of charge is placed
on the plates, it creates a potential
difference of 855 V. What is the
area of the plates?
(The answer is _*10^-5 m^2. Just fill
in the number, not the power.)
Answer:
2.39×10¯⁵ m²
Explanation:
From the question given above, the following data were obtained:
Distance (d) = 8.08×10¯⁵ m
Charge (q) = 2.24×10¯⁹ C
Potential difference = 855 V
Area(A) =?
NOTE: Permittivity (ε₀) = 8.854×10¯¹² F/m
The area can be obtained as follow:
q = ε₀AV/d
2.24×10¯⁹ = 8.854×10¯¹² × A × 855 / 8.08×10¯⁵
2.24×10¯⁹ = 7.57×10¯⁹ × A / 8.08×10¯⁵
Cross multiply
7.75×10¯⁹ × A = 2.24×10¯⁹ × 8.08×10¯⁵
7.75×10¯⁹ × A = 1.81×10¯¹³
Divide both side by 7.75×10¯⁹
A = 1.81×10¯¹³ / 7.75×10¯⁹
A = 2.39×10¯⁵ m²
Thus, the area of the plate is 2.34×10¯⁵ m²
Answer:
2.39
Explanation:
How much mass does 1 mol of O2 gas have?
O A. 16.00 x 2g
O B. 16.00 x (6.02 x 10^23) g
C. 2 x (6.02 x 10^23) g
D. 16.00 g
Answer:
Option A.
Explanation:
1 mol of anything contains 6.02×10²³ particles.
We know that 1 mol of oxygen gas contains 2 moles of O.
1 mol of oxygen weighs 16 g/mol, the mass for 1 molecule of O.
By the way, the mass for 1 mol of O₂ may be:
Option A → 16 g/mol . 2 mol
32 g
Oyxgen is a dyatomic molecule, that's why we have 2 moles of O.
Another example can be:
1 mol of water (H₂O) contains 2 moles of H and 1 mol of O.
a sample of silver has a volume of 6 cm^3 and a massage of 36 grams what's the samples density
Answer:
6g/cm³
Explanation:
Density of a substance can be calculated as follows:
Density = mass (g)/volume (cm³)
According to this question, a sample of silver has a volume of 6 cm³ and a mass of of 36g. The density will be
Density = 36/6
Density = 6g/cm³
Part C
For each source of energy, describe its strengths and weaknesses with respect to the ideal source you described in part A. Do Internet research, as needed, to describe each energy source.
Question 1
Describe at least two advantages and two disadvantages of using natural gas as a source of energy.
Answer:
See explanation
Explanation:
Natural gas is mined along with crude oil in many oil wells. It has the advantage of being a cheap fossil fuels which is easily obtainable.
Generally, natural gas is the cleanest of all the fossil fuels. This means that it is the fossil fuel that least contributes to environmental pollution.
On the other hand; natural gas produces some amount of sulphur as it is burnt and mercury as particulate matter. These substances are quite dangerous to health.
Secondly, the combustion of natural gas leads to the production of the oxides of nitrogen which play a key role in the occurrence of photochemical smog.
Can someone please help me!!
Answer:
Explanation:
Hope this helps u!!
Based on your understanding of how bond types influence a material’s properties, identify each of the following compounds as being made of ionic, covalent, or metallic bonds.
ANSWER
Steel: Metalic
Propane: Covalent
Calcium chloride: ionic
Water: Covalent
Edge 2021
Answer: The given compounds are identified as being made of ionic, covalent, or metallic bonds:
Steel - Metallic bondsPropane - Covalent bondsCalcium chloride - Ionic bondsWater - Covalent bondsExplanation:
A bond formed by transfer of electrons from one atom to another is called an ionic bond. An ionic bond is formed between a metal atom and a non-metal atom.
A bond formed by transfer of electrons from one atom to another is called a covalent bond. A covalent bond is formed between two or more non-metal atoms only.
Steel is actually an alloy of carbon and iron where there is less than 2% carbon, 1% manganese and small amounts of silicon, phosphorus, oxygen and sulphur are present.
When atoms of metals are held together then bond formed between these atoms is called metallic bond.
Hence, steel is made of metallic bond.
Chemical formula of propane is [tex]CH_{3}CH_{2}CH_{3}[/tex] as there are only non-metal atoms are present. So, sharing of electrons takes place in such atoms due to which covalent bonding will be there.
Hence, propane is made up of covalent bonds.
Calcium chloride contains a metal and a non-metal atom. This means that electrons are being transferred from calcium atom to the chlorine atom. Hence, bond present in calcium chloride is ionic bond.
Water has chemical formula [tex]H_{2}O[/tex]. Since, non-metal atoms are present there so sharing of electrons takes place between hydrogen and oxygen atoms. Hence, covalent bond is present in water.
Thus, we can conclude that given compounds are identified as being made of ionic, covalent, or metallic bonds:
Steel - Metallic bondsPropane - Covalent bondsCalcium chloride - Ionic bondsWater - Covalent bondsSteel: ✔ metallic
Propane: ✔ covalent
Calcium chloride: ✔ ionic
Water: ✔ covalent
three functions of the stem
The three functions of the stem:
To support the leaves,To conduct water, and To conduct minerals to the leaves.A student wrote a chemical equation as shown.
2H₂S+ 302 H₂O + SO₂
What should the student do to balance the equation?
Answer: The student must add 2 infront of both [tex]H_2O[/tex] and [tex]SO_2[/tex] to make the equation balanced.
Explanation:
A balanced chemical equation is one where all the individual atoms are equal on both sides of the reaction. It follows the law of conservation of mass.
For the given unbalanced chemical equation:
[tex]2H_2S+3O_2\rightarrow H_2O+SO_2[/tex]
On the reactant side:
Atoms of H = 4
Atoms of S = 2
Atoms of O = 6
On the product side:
Atoms of H = 2
Atoms of S = 1
Atoms of O = 3
To balance the equation, a student must balance the atoms by adding 2 infront of both [tex]H_2O[/tex] and [tex]SO_2[/tex]
For the balanced chemical equation:
[tex]2H_2S+3O_2\rightarrow 2H_2O+2SO_2[/tex]
How many significant digits are in the value 0.0050340?
Answer:
6
Explanation:
6, because the number after decimals are considered significant but the 0 after the last number is not significant.
PLEASE HELP WILL GIVE LOTS OF POINTS!!!!!!!!!!!! What is the daughter particle if Uranium -234 undergoes beta decay? Write your answer in isotopic notation.
Answer:
Given nuclide is uranium-234.
If it undergoes beta decay then, what will be the daughter particle?
Explanation:
The beta particle decay increases the atomic number of the nuclide by one.
There is no change in the mass number of the nuclide.
The decay of beta particle from Uranium-234 is shown below:
It forms Np-93.
Question
Calculate the total energy, in kilojoules, that is needed to turn a 35 g block
of ice at -10 degrees C into water vapor at 100 degrees C.
Answer:
34545 J
Explanation:
Applying,
E = mc'+cm(t₂-t₁)+Cm(t₂-t₀).............. Equation 1
Where E = Total energy, m = mass of the ice, c' = latent heat of ice, c = specific heat capacity of ice, t₂ = final temperature, t₁ = initial temperature, C = specific heat capacity of water, t₀ = temperature of ice at 0°C
From the question,
Given: m = 35 g = 0.035 kg, t₁ = -10°C, t₂ = 100°C, t₀ = 0°C
Constant: C = 4200 J/kg.K, c = 2100 J/kg.K, c' = 336000 J/kg
Susbtitute these values into equation 1
E = [336000(0.035)]+[0.035×2100(100+10)]+[4200×0.035(100-0)]
E = 11760+8085+14700
E = 34545 J
A hot metal plate at 150°C has been placed in air at room temperature. Which event would most likely take place over the next few minutes? Molecules in both the metal and the surrounding air will start moving at lower speeds. Molecules in both the metal and the surrounding air will start moving at higher speeds. The air molecules that are surrounding the metal will slow down, and the molecules in the metal will speed up. The air molecules that are surrounding the metal will speed up, and the molecules in the metal will slow down.
Answer:
last option is correct.
Air molecules surrounding the metal will speed up and metal molecules will slow down
Explanation:
the metal cools when placed in room temperature air which causes surrounding air to heat up.
the speed of molecules slow down for any material which cools and molecules speed increases when any material heats up
A block is pulled 0.90 m to the right in 2.4 s. What is the block's average speed to the nearest hundredths of a m/s?
what are some different natural events and man-made activities that can affect ocean acidification?
Ocean acidification is the process of decreased pH levels of the oceans. The burning of fossil fuels and industrialization are man-made activities that lead to this process.
What is Ocean acidification?Ocean acidification is an increased concentration of acidic components of the oceans due to an increase in the carbon dioxide level of the oceans.
Human activities like cutting down a large number of trees, discharging from industrial outlets, and burning fossils like petrol, coal, diesel, etc. are leading to increased acidification of the oceans.
Therefore, natural causes like increased salinity, flood, and earthquake are the reasons for oceanic acidification.
Learn more about ocean acidification here:
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Write the electron configuration for Gold (Au). You may choose to write it in the long form or in the noble gas configuration form (shortcut).
Answer:
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s¹4f¹⁴5d¹⁰
Explanation:
An electric kettle draws a current of 6.50 A while it is plugged into a 120-V
electrical outlet. What power does the kettle use?
Answer:
780 watts
Explanation:
formula to find power when given amps and voltage
P = A x V
=6.50a x 120V
= 780 W (watts)
Use the reaction N2(g) + 3H2(g) 2NH3(g) to answer the following questions
a. 1 pt: What does Le Châtelier's principle predict would happen to the equilibrium conditions if N2(g) + 3H2(g) were added to the system?
b. 1 pt: What would happen to the equilibrium if the pressure were decreased?
c. 2 pts: Write the equation for calculating Keq
d. 3 pts: Calculate the value for Keq given the following concentrations
[NH3] = 6 M
[H2] = 4 M
[N2] = 3 M
Answer:
Explanation:
a ) If N₂(g) and 3H₂(g) is added to the system , 2 moles of additional ammonia will be produced .
b ) If pressure is decreased , less amount of ammonia will be formed, because forward reaction reduces the pressure. So, reaction will take place in reverse direction.
c ) Keq = [ NH₃ ] ² / [ N₂ ] [ H₂]³
d ) Substituting the given values in the equation ,
Keq = [ 6M ] ² / [ 3M] [ 4M]³
= 36 / 3 x 64 M⁻²
= 18.75 x 10⁻² M⁻² .
which of the following is a property of acids
A. they are slippery
B. They taste bitter
C. They react with oils
D. they are sour
Answer:
They are sour. =)
Explanation:
Why would the electrolysis reaction stop if the battery was removed
If the battery was removed, the energy produced by the battery would not be able to continue its path along the circuit.
what is a metal ore?
Answer:
metal ores are naturally occurring rocks that contain metals or metal compounds in sufficient amounts to make it worthwhile extracting them
Se realiza una mezcla de minerales de Cu y Fe: 20 kg FeS2 (pirita), 70 kg de Fe2O3 (hemetita) 15 kg de CuFe2 (calcopirita) y 90 kg de CuO (tenorita). Calcule: Porcentaje de hierro Porcentaje de cu Porcentaje de azufre y oxigeno
Answer:
34.78% Fe
39.66% Cu
5.48% S
20.07% O
Explanation:
Para resolver esta pregunta debemos hallar la masa de cada átomo en cada mineral. Así, podremos hallar el porcentaje de cada átomo:
Pirita (Fe: 55.845g/mol; S: 32.065g/mol; FeS2: 119.975g/mol)
Masa Fe:
20kg FeS2 * (1*55.845g/mol / 119.975g/mol) = 9.31kg Fe
Masa S:
20kg FeS2 * (2*32.065g/mol / 119.975g/mol) = 10.69kg S
Hemetita (Fe: 55.845g/mol; O: 16g/mol; Fe2O3: 159.688g/mol)
Masa Fe:
70kg Fe2O3 * (2*55.845g/mol / 159.688g/mol) = 48.96kg Fe
Masa O:
70kg Fe2O3 * (3*16g/mol / 159.688g/mol) = 21.04kg O
Calcopirita (Fe: 55.845g/mol; Cu: 63.546g/mol; CuFe2: 175.236 g/mol)
Masa Fe:
15kg CuFe2 * (2*55.845g/mol / 175.236 g/mol) = 9.56kg Fe
Masa Cu:
15kg CuFe2 * (1*63.546g/mol / 175.236 g/mol) = 5.44kg Cu
Tenorita (O: 16g/mol; Cu: 63.546g/mol; CuO: 79.545 g/mol)
Masa O:
90kg CuO * (1*16g/mol / 79.545 g/mol) = 18.10kg O
Masa Cu:
90kg CuO * (1*63.546g/mol / 79.545 g/mol) = 71.90kg Cu
Masa Total: 20kg + 70kg + 15kg + 90kg = 195kg
Porcentaje Hierro:
9.31kg Fe + 48.96kg Fe + 9.56kg Fe / 195kg * 100 =
34.78% Fe
Porcentaje Cobre:
5.44kg Cu + 71.90kg Cu / 195kg * 100 =
39.66% Cu
Porcentaje Azufre:
10.69kg S / 195kg * 100 =
5.48% S
Porcentaje Oxígeno:
21.04kg O + 18.10kg O/ 195kg * 100 =
20.07% O
The compounds that form from the bonding of the hydroxyl group (-OH) to a hydrocarbon are called the aldehydes.
True
False
Answer:
False.
I just got it right, lol.
