Answer:
54 days
Explanation:
We have to use the formula;
0.693/t1/2 =2.303/t log Ao/A
Where;
t1/2= half-life of phosphorus-32= 14.3 days
t= time taken for the activity to fall to 7.34% of its original value
Ao=initial activity of phosphorus-32
A= activity of phosphorus-32 after a time t
Note that;
A=0.0734Ao (the activity of the sample decreased to 7.34% of the activity of the original sample)
Substituting values;
0.693/14.3 = 2.303/t log Ao/0.0734Ao
0.693/14.3 = 2.303/t log 1/0.0734
0.693/14.3 = 2.6/t
0.048=2.6/t
t= 2.6/0.048
t= 54 days
Consider the equation below.
Zn + H2SO4 → ZnSO4 + H2
The mole ratio of zinc to zinc sulfate is
Answer:
1:1
Explanation:
There is one mole of zinc (Zn) and one mole of zinc sulfate (ZnSO₄).
The mole ratio is 1:1.
Hope this helps.
Answer:
1:1
Explanation:
what happens to the concentration of a product over the course of a reaction
Answer:
it becomes poisonous to the body
Name one way chemicals can help the environment
Energy storage and transport. Chemical energy transport.
Answer:
to clean the water
Explanation:
Which tool was used to collect the solid product of the chemical reaction? the balance the funnel with the filter paper the Erlenmeyer flask the beaker the watch glass With this tool, the could be separated from the .
Answer:
B. The Funnel withe the filter paper.
Explanation:
The next answers is copper and aqueous solution.
The statement, that describes tool was used to collect the solid product of the chemical reaction is "the funnel with the filter paper."
What is a chemical reaction ?
A chemical reaction is a process that converts one or more compounds, known as reactants, into one or more distinct substances, known as products.
Filtration is a basic process for removing solid particles suspended in a liquid solution. Filtration is a method of separating solids from liquids or gases by employing a filter material that enables the fluid but not the solid to pass through. A funnel with filter paper can be used to gather solid product during the filtration process.
Hence the correct answer is the funnel with the filter paper.
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if 140cm3 of methane diffuse into air in 72 sec,how long will it take 210cm3 of sulphur dioxide to diffuse under the same condition ?
Answer:
time for sulphur dioxide to diffuse is 221.05 secs
The time for sulphur dioxide to diffuse is 108 sec.
Which gas diffuses twice quickly as SO2?Sulfur dioxide has a molecular weight of sixty-four and as a result, the square root is 8. since its inversely proportional, on the way to diffuse two times as fast, the rectangular root of the molecular weight should be 4, and subsequently the molecular weight might be 16. So the solution is methane (CH4).
Which gases diffuse the fastest?The charge of diffusion for a gas is inversely proportional to the rectangular root of its molecular mass (Graham's law). The gasoline with the lowest molecular weight will effuse the fastest. The lightest, and consequently fastest, fuel is helium.
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Which are characteristics of a prokaryotic cell? Select three options. contains DNA lacks DNA contains ribosomes lacks ribosomes contains a nucleus lacks a nucleus
Answer:
Prokaryotic cells contain DNA, contain ribosomes, and lack a nucleus.
Answer:
Contains DNA
Contains Ribosomes
lacks a nucleus
Explanation: I took the quiz on edge
hurry I'm on a timer
Which term describes erosion?
O creates small particles
O hardens rock fragments
O transports solid materials
O dissolves rock components
Answer:
transports solid materials
Explanation:
Erosion is a process where solid materials are transported by natural forces such as wind or water.
Answer: c
Explanation:
How are the properties of metals and non-metals different?
Answer:
Explanation:
Properties of metals:
1. They have a lustre ( shine )
2. They have a silvery-grey or golden-yellow colour.
3. They conduct heat and electricity.
4. They are ductile ( can be drawn into wires ) .
5.They are malleable ( can be hammered into thin sheets ).
6. They are sonorous ( make a ringing sound when hit ).
Properties of non-metals:
1. They display a variety of colours.
2. They are poor conductors of heat and electricity.
3. They are not lustrous, ductile or malleable.
Hope it helps
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While camping you light a small campfire, initiating the combustion of wood to produce heat and
light. What can you determine about this reaction?
O A. It is exothermic.
B. The bond making energy is more than 600 kJ.
OC. It is endothermic.
D. The bond breaking energy is more than 600 kJ.
Answer:
A. It is exothermic
Explanation:
Combustion is a chemical reaction in which a substance combines with oxygen present in air to produce carbon (iv) oxide and water as well release heat and light energy.Combustion is an exothermic process.
An exothermic reaction releases energy in the form of heat to the surroundings. The energy required to break bonds in the reactants is less than the energy required to form new bonds in the products in an exothermic reaction.
From the given options;
A. It is exothermic is determinable since the reaction is a combustion reaction
B. The bond making energy is more than 600 kJ is not certain because the mass of the wood being burnt is not given. Also, wood is not composed of a specific element that would be taking part in the reaction, rather it is composed of various substances.
C. It is endothermic. is wrong because combustion of wood is exothermic.
D. The bond breaking energy is more than 600 kJ is not certain because the mass of the wood being burnt is not given. Also, wood is not composed of a specific element that would be taking part in the reaction, rather is composed of many substances.
How do you find the amount of electrons for any element?
Answer:
If you know the number of protons and neutrons you have to simply subtract the number of neutrons by number of protons the answer will be number of neutron
Explanation:
Answer:
We can find the amount of electrons through its Atomic number and with the help of electronic configuration
Hi does anyone know how to do question 4?
Please show working out thanks.
answer:
a)1.274 g b) 0.013 mole
Explanation:
a) Mass of 1 mol of CuSo4. 5H20=
[tex]63 + 32 + (16 \times 4) + (7 \times 1) + (16 \times 5)[/tex]
=246g
no. moles of CuSo4. 5H2O=
[tex] \frac{mass}{mass \: of \: 1mole} [/tex]
so moles
=
[tex] \frac{3.14}{246} [/tex]
0.013 mole
in the equation
1 mole of sulphuric acid reacts to form 1 mole of CuSo4.5H2O
in other words
0.013 mole of sulphuric acid reacts to form 0.013 mole of CuSo4.5H2O
so mass of 1 mole (Mr) H2So4=
[tex](2 \times 1) + 32 + (16 \times 4)[/tex]
98g
mass of sulphuric acid= mole × mass of 1 mole
so mass= 0.013 × 98
1.274 g
b) In the equation
1 mole of sulphuric acid reacts to form 1 mole of copper(ll) oxide
in other words
0.013 mole of sulphuric acid reacts to form 0.013 mole of copper (ll) oxide
so 0.013 mole of copper(ll) oxide is reacted
Hope it helped and pls mark brainliest
Calcium (Ca) has an atomic number of 20. It can form an ion by losing 2
electrons. What would its charge be?
A. 18
B. 22
C. 2+
D. 2-
Answer:
2+
Explanation:
Apex lolz
A student combines 364.6 g of HCl with 80 g of NaOH in 5 L of water. What additional volume of H2O must be added to this mixture to yield a solution with a pH of 1? Note that the molar mass of HCl is 35.46 g/mole, while that of NaOH is 40 g/mole.
Answer:
75L of additional water to have a pH 1 solution
Explanation:
The reaction of HCl With NaOH is:
HCl + NaOH → H₂O + NaCl
By using molar mass of each reactant you can know how many moles will react, thus:
HCl: 364.6g HCl ₓ (1mol / 36.46g) = 10 moles HCl
NaOH: 80g NaOH ₓ (1mol / 40g) = 2 moles NaOH
That means after the reaction will remain in solution, 10-2 = 8 moles of HCl = 8 moles of H⁺ (In water, HCl dissociates as H⁺ and Cl⁻ ions).
A solution with pH = 1 contains:
pH = -log [H⁺]
1 = -log [H⁺]
0.1M = [H⁺]
As molarity, M is the ratio between moles and liters and you want a solution 0.1M having 8 moles of H⁺ you require:
0.1M = 8 moles H⁺ / 80L
As the student combines the solution with 5L of water, you require
75L of additional water to have a pH 1 solution4.Acrylic fibres are also known as
a)Terry cot
b)Orlon
c)Polyester
d)None of these
Answer:
B
Explanation:
DuPont created the first acrylic fibers in 1941 and trademarked them under the name Orlon.
first ionization energy
Answer:
The first ionization energy is defined as
Energy which is required to pull out one mole of the outermost shell's electrons in a neutral atom from one mole of gaseous atoms to produce 1 mole of gaseous ions each with a charge of 1+.[tex]A\to A^++ e^{-}[/tex] , where A is any neutral atom.In the periodic table, Its value decreases from top to bottom in groups and increases from left to right across a particular period. Helium has the largest first ionization energy.Francium has one of the lowest.Calculate the amount of gold deposited when a current of 5A is passed through a solution of gold salt for 2hrs 15mins. If the same current is used, find the time taken for 6g of gold to be deposited. (Au=197 1faraday=96500c)
Answer:
a. 82.68 g b. 9.8 min
Explanation:
a. The amount of gold deposited by 5 A current in 2 hrs 15 mins
Since charge Q = It where I = current = 5 A and time = 2 hrs 15 mins = 2 × 60 min + 15 min = 120 + 15 min = 135 min = 135 × 60 s = 8100 s
Q = 5 A × 8100 s
= 40500 C
Also, Q = nF where n = number of moles of gold deposited and F = Faraday's constant = 96500 C
n = Q/F = 40500 C/96500 C = 0.4195 moles ≅ 0.42 mole
Now n = m/M where m = mass of gold and M = molar mass of gold = 197
m = nM
= 0.42 × 197 g
= 82.68 g
b. The time taken for 6g of gold to be deposited.
We first find the number of moles of gold in 6g of gold
Since n = m/M and m = 6 g
n = 6/197 = 0.0305 mole
Q = It = nF
t = nF/I
= 0.0305 mol × 96500 C/5 A
= 2939.09 mol C
= 587.82 s
Changing t to minutes
587.82/60 s = 9.8 min
write down the new substance formed when ammonia react with hydrochloric acid
Answer: ammonium chloride
Explanation: The reaction equation among ammonia (NH3) and hydrochloric acid (HCl) is written as follows: NH3+HCl=NH4Cl. Ammonia is a susceptible base that reacts with hydrochloric acid, forming a compound referred to as ammonium chloride.
Anyone know how to answer this?
Answer:
i metal
ii nonmetal
iii metal
iv nonmetal
Explanation:
If you look up what the element of a heater is, you get a picture of some sort of rod. It's the heating element of the heater, and must be some type of metal to conduct electricity and warm up. Fishing rods are made of either fiberglass, graphite, or carbon fibre. These are nonmetals. In order for a lightning rod to conduct electricity and bring the lightning down to the ground, it has to be metal. You wouldn't want a metal oven mitt, as that would burn your hand.
(PLEASE HELP, LAST QUESTION I NEED! ) Describe to me the purpose of stoichiometry calculations.
Explanation:
Stoichiometry measures these quantitative relationships, and is used to determine the amount of products and reactants that are produced or needed in a given reaction. Describing the quantitative relationships among substances as they participate in chemical reactions is known as reaction stoichiometry.
Need help ASAP!!!! what is the value (angle) for the C=C=O bond in Ketene i.e. CH2=C=O
Answer:
[tex]180^\circ[/tex] by the VSEPR theory.
Explanation:
This question is asking for the bond angle of the [tex]\rm C=C=O[/tex] bond in [tex]\rm H_2C=C=O[/tex]. The VSEPR (valence shell electron pair repulsion) theory could help. Start by considering: how many electron domains are there on the carbon atom between these two bond?
Note that "electron domains" refer to covalent bonds and lone pairs collectively.
Each nonbonding pair (lone pair) of valence electrons counts as one electron domain.Each covalent bond (single bond, double bond, or triple bond) counts as exactly one electron domain.For example, in [tex]\rm H_2C=C=O[/tex], the carbon atom at the center of that [tex]\rm C=C=O[/tex] bond has two electron domains:
This carbon atom has two double bonds: one [tex]\rm C=C[/tex] bond and one [tex]\rm C=O[/tex] bond. Even though these are both double bonds, in VSEPR theory, each of them count only as one electron domain. Keep in mind that there are only four valence electrons in each carbon atom. It can be shown that all four valence electrons of this carbon atom are involved in bonding (two in each of the two double bonds.) Hence, there would be no nonbonding pair around this atom.In VSEPR theory, electron domains around an atom repel each other. As a result, they would spread out (in three dimensions) as far away from each other as possible. When there are only two electron domains around an atom, the two electron domains would form a straight line- with one domain on each side of the central atom. (To visualize, consider the three atoms in this [tex]\rm C=C=O[/tex] bond as three spheres on a stick. The central [tex]\rm C[/tex] atom would be between the other [tex]\rm C[/tex] atom and the [tex]\rm O[/tex] atom.)
This linear geometry corresponds to a bond angle of [tex]180^\circ[/tex].
Research how different fossil fuels compare in terms of the amount of carbon dioxide released per kWh of energy. How much carbon dioxide is produced by burning a gallon of gasoline? A gallon of diesel?
Answer:
About 19.64 pounds of carbon dioxide are produced from burning a gallon of gasoline. On the other hand, 22.38 pounds of carbon dioxide are produced from burning a gallon of diesel. So, different fossil fuels will give different amounts of carbon dioxide to be released.
Explanation:
For biomass, solar, coal, natural gas, oil, and geothermal energy, identify each energy resource as renewable or non-renewable.
Answer:
biomass is renewable
solar is renewable
coal is non-renewable
natural gas is non-renewable
oil is non-renewable
geothermal energy is renewable
Explanation:
The biomass, solar and geothermal are renewable source of energy and coal, natural gas and oil are non renewable source of energy.
What is renewable source of energy?Renewable energy is defined as the energy derived from natural source of energy that are replenished at the higher rate then they are consumed.
It can also be defined as the energy that are collected from renewable resources that are replenished on a human time scale.
Solar, wind, tidal, biomass, geothermal etc. are some of the example.
Non renewable energy is defined as the natural resource of energy that cannot be easily replaced by human means at a pace quickly enough to keep up with the consumption.
Coal, petrol, oil, natural gas, fossil fuel etc. are some of the example.
Thus, the biomass, solar and geothermal are renewable source of energy and coal, natural gas and oil are non renewable source of energy.
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in Analytical chemistry laboratory. Nickle(ppm)in water sample estimated by two different students was as ,student 1 (25 24 24 24 24 28 26 ) and student 2 (24 25 24 24 25 25 ), if the true valude on Nickle in water was 20 ppm estimate the precision and accuracy of both students
Answer:
Answers are in the explanation
Explanation:
Precision and accuracy are both statistical concepts. Precision is about how close are the measured values to each other. Accuracy is closeness of the measured values to a specific value or reference value.
There are many ways to calculate precision and accuracy, one is stimating precision as Relative Uncertainty and accuracy as Relative Error.
Formulas are:
Relative Uncertainty: Standard desviation / Measured value.
Relative Error: Measured Value - Expected Value / Expected value
Measured value is the aveage of the values.
For student 1:
Mean = 25
Standard desviation = 1.5275
Relative Uncertainty: 1.5275 / 25
Relative Uncertainty: 0.061
Relative Error: 25 - 20 / 20
Relative Error: 0.25
For student 2:
Mean = 24.5
Standard desviation = 0.5477
Relative Uncertainty: 0.5477 / 24.5
Relative Uncertainty: 0.02
Relative Error: 24.5 - 20 / 20
Relative Error: 0.225
As the student 2 has a low Relative error and uncertainty, you can say student 2 is more accurate and precise
Acid rain is the direct result of acid released by burning fossil fuels.
Please select the best answer from the choices provided
ОТ
OF
Answer:
The answer is TrueHope this helps you
A pressure cooker contains 5.68 liters of air at a temperature of 394 K. If the absolute pressure of the air in the pressure cooker is 205 pascals, how many moles of air are in the cooker? The cooker contains _______ moles of air.
Answer:
The pressure cooker contains 0.000355 moles of air (to three significant figures).
Explanation:
To find the number of moles of air in the pressure cooker, we can use the ideal gas law.
Ideal Gas Law[tex]PV=nRT[/tex]
where:
P is the pressure measured in pascal (Pa).V is the volume measured in cubic meters (m³).T is the temperature measured in kelvin (K) R is the ideal gas constant (8.3144626 J·K/mol).n is the number of moles.Rearrange the equation to solve for n:
[tex]\implies n=\dfrac{PV}{RT}[/tex]
As we have been given the volume in liters, we must first convert it to cubic meters. As 1 liter = 0.001 m³ then 5.68 liters = 0.00568 m³.
Therefore, the values to substitute into the formula are:
P = 205 PaV = 0.00568 m³T = 394 KR = 8.3144626 J·K/molSubstitute the values into the formula and solve for n:
[tex]\implies n=\dfrac{205 \cdot 0.00568}{8.3144626 \cdot 394}[/tex]
[tex]\implies n=0.000355444...[/tex]
[tex]\implies n=0.000355\; \sf mol\; (3\;s.f.)[/tex]
Therefore, the pressure cooker contains 0.000355 moles of air (to three significant figures).
Determine the net iconic equation for the following chemical reaction: HCl(aq) + NH4OH(aq)———-> NH4Cl(aq) + H2O(I) Hint: HCl(aq) is strong acid NH4OH(aq) is a weak base
Answer : The net ionic equation will be,
[tex]H^{+}(aq)+OH^{-}(aq)\rightarrow H_2O(l)[/tex]
Explanation :
In the net ionic equations, we are not include the spectator ions in the equations.
Spectator ions : The ions present on reactant and product side which do not participate in a reactions. The same ions present on both the sides.
The given balanced ionic equation will be,
[tex]HCl(aq)+NH_4OH(aq)\rightarrow NH_4Cl(aq)+H_2O(l)[/tex]
The ionic equation in separated aqueous solution will be,
[tex]H^+(aq)+Cl^-(aq)+NH_4^+(aq)+OH^-(aq)\rightarrow H_2O(l)+NH_4^+(aq)+Cl^-(aq)[/tex]
In this equation, [tex]NH_4^+\text{ and }Cl^-[/tex] are the spectator ions.
By removing the spectator ions from the balanced ionic equation, we get the net ionic equation.
The net ionic equation will be,
[tex]H^{+}(aq)+OH^{-}(aq)\rightarrow H_2O(l)[/tex]
A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion. B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion. C. If Assertion is true statement but Reason is false. D. If Assertion is false and Reason is true i Assertion: .Burning of magnesium ribbon produce whitish powder called magnesium oxide. Reason : Magnesium is generally cleaned by rubbing it on sand paper
Answer:
C. If Assertion is true statement but Reason is false.
Explanation:
The burning of magnesium in air produces magnesium oxide as shown by the equation;
2Mg(s) + O2(g) -----> 2MgO(s)
The magnesium oxide solid is recovered as a white ash. This is a typical example of an oxidation reaction which is also a combustion reaction.
The reason has nothing at all to do with the assertion hence the answer given.
Magnesium oxide is basic just like the oxides of other metals and dissolves in water to yield an alkali.
Answer:
Answer:
C. If Assertion is true statement but Reason is false.
Explanation:
The burning of magnesium in air produces magnesium oxide as shown by the equation;
2Mg(s) + O2(g) -----> 2MgO(s)
The magnesium oxide solid is recovered as a white ash. This is a typical example of an oxidation reaction which is also a combustion reaction.
The reason has nothing at all to do with the assertion hence the answer given.
Magnesium oxide is basic just like the oxides of other metals and dissolves in water to yield an alkali.
Explanation:
Based on the law of Conservation of Mass, what happens to the mass of a substance in a chemical change? A: the mass is always conserved B: The mass is either created or destroyed C: the reactant always has more mass D: the product always has more mass
Answer:
A.
Explanation:
The amount of mass always stays the same, matter cannot be created nor destroyed, it can only change forms. Thus, the answer is A.
In a chemical reaction the total mass of all the substances taking part in the reaction remains the same. Also, the number of atoms in a reaction remains the same. Mass cannot be created or destroyed in a chemical reaction.
I hope this helps..
Match the following.
1. A substance that produces hydrogen ions in solution; alternatively, a proton donor
2. A substance that produces hydroxide ions in solution; alternatively, a proton acceptor
a. acid
b. base
Answer:
1. Acid produces hydrogen ions in a solution.
2. Base produces hydroxide ions in a solution.
Answer:
1. A substance that produces hydrogen ions in solution; alternatively, a proton donor
Acid
2. A substance that produces hydroxide ions in solution; alternatively, a proton acceptor
Base
Which of the following is NOT an indicator of a chemical
reaction?
O A. Breaking into small pieces
OB. Producing a solid
OC. Changing color
OD. Producing light
Answer:OD. Producing light
Explanation: