Answer:
1.115 g
Explanation:
Applying,
R = R'[tex]2^{n/t}[/tex]................... Equation 1
Where R = original sample of radon-222, R' = sample of radon-222 left after decay, n = Total time, t = half-life.
make R' the subject of the equation
R' = R/([tex]2^{n/t}[/tex])............... Equation 2
From the question,
Given: R = 73.9 g, n = 23 days, t = 3.8 days.
Substitute these values into equation 2
R' = 73.9/([tex]2^{23/3.8}[/tex])
R' = 73.9/[tex]2^{6.05}[/tex]
R' = 1.115 g
The radiostope radon 222 has a half life of 3.8 days. How much of a 73.9-g sample or radon 222 wouppd be left after 23 days ?? pls show an equation
Answer:
Is there a picture for it
Explanation:
because it would be a hard
What is the volume of 2.66 x 10^23 molecules of N2 gas at STP? PLEASE ANSWER WITH WORK! ILL GIVE BRAINLIEST
Answer:
1100L.
Explanation:
The strength of the gravitational attraction depends on the mass of the objects involved and the distance between them. The gravitational force between two objects will be lowest in which of the following situations?
A. Both objects have small masses and are close together.
B. One object has a large mass, and the objects are close together.
C. Both objects have large masses and are close together.
D. Both objects have small masses and are far apart.
Answer:
d sguro
Explanation:
I'm not sure kung ayan ba
What is a balanced nuclear equation for the alpha decay of Strontium-90?
Answer: The balanced nuclear equation for the alpha decay of Sr-90 is [tex]_{38}^{90}\textrm{Sr}\rightarrow _{36}^{86}\textrm{Kr}+_2^4\alpha[/tex]
Explanation:
A nuclear reaction is defined as the reaction in which the changes in the nucleus of an atom take place and usually form a different element. The types of decay processes are:
Alpha decayBeta-decayGamma decayAlpha decay is the process in which a heavy nucleus decays into a light nucleus with the release of an alpha particle. This alpha particle carries a charge of +2 units and has a mass of 4 units. It is also known as the helium nucleus. The general equation for this decay process is:
[tex]X_Z^A\rightarrow Y_{Z-2}^{A-4}+\alpha _2^4[/tex]
The nuclear equation for the alpha decay of strontium-90 isotope follows:
[tex]_{38}^{90}\textrm{Sr}\rightarrow _{36}^{86}\textrm{Kr}+_2^4\alpha[/tex]
an unknown gas diffuses 1.25 times faster than CO2 gas. What is the molar mass of the unknown gas?
Answer:
28.16 g/mol
Explanation:
From Graham's law;
Let the rate of diffusion of gas X be 1.25
Let the rate of diffusion of CO2 be 1
Molecular mass of gas X= M
Molecular mass of CO2 = 44g/mol
1.25/1=√44/M
(1.25/1)^2 = 44/M
1.5625 = 44/M
M= 44/1.5625
M= 28.16 g/mol
Michael is studying the factors that affect corrosion of metals. He wants to test the effect that different concentrations of an acid will have on the corrosion of a metal. As he sets up and completes his experiment, which of the following experimental designs would be most likely to help him answer his question? A. Allow several metal samples to soak in different amounts of acid of a single concentration and then measure the amount of corrosion on each. B. Prepare solutions of different acid concentrations, measure 50 milliliters of each into different beakers, and place metal samples of different types but of the same mass into the beakers. C. After allowing several small metal sheets to be exposed to different acid concentrations, measure the surface area of each that is corroded. D. After allowing a small metal sheet to be exposed to one acid concentration, place it in different acid concentrations, then measure the surface area that is corroded.
Answer:
B. Prepare solutions of different acid concentrations, measure 50 milliliters of each into different beakers, and place metal samples of different types but of the same mass into the beakers.
Explanation:
Since Michael is studying the factors that affect corrosion of metals, and wants to test the effect that different concentrations of an acid will have on the corrosion of a metal, using different acid concentrations of the same volume on different metal samples of the same size would give a much better than all the other options because, a standard volume of acid is used and also a standard mass of metal is used. So, the effect can be measured quantitatively since we have the same quantity of sample.
So, option B is the answer
What plate forms a boundary with the African plate
Answer:
The Eurasian plate(another major plate), the Aegean sea plate and the Anatolian plate share the north border. The Antarctic plate that contributes to the south of the African plate, is also a major plate.
water is to ____as liquid is to soild
water is to gas as liquid is to solid
copper +sulfur + oxygen =
Calculate the total amount of energy required in calories to convert 50.0 g of ice at 0.00 degrees Celsius to steam at 100. degrees Celsius.
Specific heat capacity of water is 1.00 cal/g OC
Hfusion = 80 cal/g OC and Hvap = 540 cal/g OC
Write the complete equation you will use. 1 point
Substitute the values in the equation in step 1. 1 point
Report the math answer with 3 sig figs and the correct unit. 1 point
Answer:
HFusion*mass + Spec.Heat*mass*ΔT + HVap*mass
80cal/g*50.0g + 1.00cal/g°C*50.0g*(100°C-0°C) + 540cal/g*50g
3.60x10⁵cal
Explanation:
Using the HFusion we can find the heat needed to convert the ice to liquid water.
With specific heat capacity we can find the heat needed to increase the temperature of water from 0 to 100°C.
With HVap we can find the heat to convert the liquid water into steam.
The equations are:
HFusion*mass + Spec.Heat*mass*ΔT + HVap*massComputing the values:
80cal/g*50.0g + 1.00cal/g°C*50.0g*(100°C-0°C) + 540cal/g*50g36000cal =
3.60x10⁵calIf a shell can hold a maximum of 32 electrons, what is the value of n?
Answer:
The value of N would be 4.
Explanation:
The equation would be 2n^x = 32 and therefore, 4.
1) list at least four uses of metals from your day to day life.
Answer:
alloy,copper,gold, silver,cobalt
Explanation:
What is the enthalpy of reaction?
O A. The amount of mass involved in a reaction
O B. The heat released or absorbed in a reaction
C. The amount of heat a substance can hold
D. A measure of the temperature of a system
Answer:
Enthalpy is the amount of heat released or absorb. The total enthalpy can be found by subtracting the products' enthalpy by the reactants' enthalpy
Given 7 moles of nitrogen gas, how many moles of ammonia can you make?
Explanation:
just use the molar ratios to figure it out. Notice, you have to balance the chemical equation.
Does a reaction involving an acid and a base have to take place in a water environment? Justify your answer.
Answer:
YES!!!
Explanation:
Strong acids and strong bases are both strong electrolytes. In contrast, only a fraction of the molecules of weak acids and weak bases react with water to produce ions, so weak acids and weak bases are also weak electrolytes.
State three pieces of evidence from the diagram which indicate that the plant is pollinated by wind. ( 3 marks)
Your image is saying "Can't load image on this device."
ELECTRICITY IS ALLOWED TO PASS THROUGH ACIDIFIED WATER USING THE FOLLOWING EXPERIMENTAL SETUP.
QUESTION: IDENTIFY THE PROCESS
Answer: Electrolysis is passing an electric current through a liquid containing ions so that decomposition reaction takes place.
Electrolysis is passing an electric current through a liquid containing ions so that decomposition reaction takes place.When an electric current is passed through acidified water, it decomposes to give hydrogen and oxygen gas. The hydrogen gas is obtained at the cathode and the oxygen gas is obtained at the anode.
Electrolysis is passing an electric current through a liquid containing ions so that decomposition reaction takes place.When an electric current is passed through acidified water, it decomposes to give hydrogen and oxygen gas. The hydrogen gas is obtained at the cathode and the oxygen gas is obtained at the anode.The reaction for decomposition of water into oxygen and hydrogen is as follows:
Electrolysis is passing an electric current through a liquid containing ions so that decomposition reaction takes place.When an electric current is passed through acidified water, it decomposes to give hydrogen and oxygen gas. The hydrogen gas is obtained at the cathode and the oxygen gas is obtained at the anode.The reaction for decomposition of water into oxygen and hydrogen is as follows:2H2O(l) -------> 2H2(g) + O2(g)
7. A sample of methane gas (CH.) with a mass of 58 g is kept in a 1500 mL container at a temperature of 100. °C. What is the pressure of the gas?
Answer:
c i took the text
Explanation:
What factor makes it possible for animals with endoskeletons to grow larger than animals with exoskeletons?
A. Endoskeletons can be removed and replaced.
B. Endoskeletons are lighter than exoskeletons.
C. Endoskeletons are made of fluid-filled tubes.
D. Endoskeletons lack joints that can break down.
i need help
Matter takes up _____.
(a) Space and temperature
(b) Space and heat
(c) Space and mass
(d) Heat and temperature
PLZ HELP!!! What mass of [tex]SrF_{2}[/tex] can be prepared from the reaction of 10.0g [tex]Sr(OH)_{2}[/tex] with excess HF? THANK U!!
Answer:
Approximately 10.5g or 10.4g [tex]SrF_{2}[/tex]
can someone explain the answer.
Answer:
A
Explanation:
Alkanes undergo substitution reaction with halogen molecules in the presence of light. This reaction occurs by free radical mechanism and the initiation step is the formation of the halogen radical.
The propagation steps involves the abstraction of a hydrogen from the alkane by the halogen radicals.
The termination steps involves the coupling of alky radicals.
Thus for the reaction of ethane and chlorine;
C2H6 + Cl2 -------> C2H5Cl + HCl
Which equation represents the correct net ionic equation for the reaction between Ca(OH)2 and H2SO4?
Upper H superscript plus, plus upper O upper H superscript minus right arrow upper H subscript 2 upper O.
2 upper H superscript plus, plus 2 upper O upper H superscript minus right arrow upper H subscript 2 upper O.
Upper C a superscript 2 plus, plus 2 upper O upper H superscript minus, plus upper S upper O subscript 4 superscript 2 minus right arrow upper C a superscript 2 plus, plus upper S upper O subscript 4 superscript 2 minus, plus 2 upper H subscript 2 upper O.
Upper C a (upper O upper H) subscript 2 plus upper H subscript 2 upper S upper O subscript 4 right arrow upper C a upper S upper O subscript 4 plus 2 upper H subscript 2 upper O.
Answer: The correct net ionic equation for the reaction is [tex]2H^{+}(aq)+2OH^{-}(aq)\rightarrow 2H_2O(l)[/tex]
Explanation:
Net ionic equation is defined as the equations in which spectator ions are not included.
Spectator ions are the ones that are present equally on the reactant and product sides. They do not participate in the reaction.
The balanced molecular equation is:
[tex]Ca(OH)_2(aq)+H_2SO_4(aq)\rightarrow CaSO_4(aq)+2H_2O(l)[/tex]
The complete ionic equation follows:
[tex]Ca^{2+}(aq)+2OH^-(aq)+2H^+(aq)+SO_4^{2-}(aq)\rightarrow 2Ca^{2+}(aq)+SO_4^{2-}(aq)+H_2O(l)[/tex]
As calcium and sulfate ions are present on both sides of the reaction. Thus, they are considered spectator ions.
The net ionic equation follows:
[tex]2H^{+}(aq)+2OH^{-}(aq)\rightarrow 2H_2O(l)[/tex]
Hence, the correct net ionic equation for the reaction is [tex]2H^{+}(aq)+2OH^{-}(aq)\rightarrow 2H_2O(l)[/tex]
Answer:
B. no reaction
Explanation:
Barbara is conducting an experiment to observe heat flow. She places one piece of metal in a freezer at -18 degrees Celsius (°C) and a second piece of metal in an oven at 200 °C. After 2 hours, she takes the metal pieces out of the freezer and oven and places them both in the same beaker of boiling water for two minutes. Which of the following best describes how some of the heat will initially move in this system?
Heat will flow from the frozen metal into the hot metal.
Heat will flow from the boiling water into the hot metal.
Heat will flow from the boiling water into the frozen metal.
Heat will flow from the frozen metal into the boiling water.
Answer: The correct answer is heat will flow from the boiling water into the frozen metal.
Explanation:
According to the law of conservation of energy, energy cannot be destroyed nor created but it can be transformed from 1 form to another form.
There are 3 processes of heat transfer:
Conduction: This type of heat transfer occurs when there is direct contact between the two objects.Convection: This type of heat transfer occurs when there is a movement of fluid (liquid or gas) due to the movement of hot layers to the top and cold layers to the bottom which leads to convection currents. Radiation: This type of heat transfer occurs when there is a direct transfer of energy through space.The heat moves from a hot surface to a cold surface to maintain equilibrium.
We are given:
A metal is placed in a freezer (cold object) and another metal is placed in an oven (hot object) and then both the metals are placed in boiling water.
Initially, the heat will flow from the boiling water (hot object) into the frozen metal (cold object) to maintain equilibrium
Hence, the correct answer is heat will flow from the boiling water into the frozen metal.
How does radon move up through rock and soil?
I have a exam please answer fast
Answer:
C
[tex] \triangle \: H {}^{ \theta} _{s} = lattice \: energy + hydration \: energy \\ = + 2526 + ( - 2003 + (2 \times - 340)) \\ + 2526 - 2683 \\ = - 157 \: kjmol {}^{ - 1} [/tex]
EJEMPLOS DE SOLUCIONES QUÍMICAS EN LA NATURALEZA
ahí esta la respuesta espero que te sirva
Look at the activity series and select which two of the following reactions would happen on their own. (Remember, if the lone element is more active than the metal in the compound, the lone element will react and replace the metal in the compound.) Lithium (Li)
Potassium (K)
Calcium (Ca)
Sodium (Na)
Aluminum (Al)
Zinc (Zn)
Iron (Fe)
Tin (Sn)
Lead (Pb)
(Hydrogen) (H)
Copper (Cu)
Silver (Ag)
Gold (Au)
A.
2Li + ZnBr2 ->2LiBr + Zn
B.
Al + 3LiCl ->AlCl3 + 3Li
C.
Sn + ZnSe ->SnSe + Zn
D.
3Ca + Al2O3 ->2Al + 3CaO
Answer:
2Li + ZnBr2 ->2LiBr + Zn
3Ca + Al2O3 ->2Al + 3CaO
Explanation:
Spontaneous reactions are reactions that can happen on their own. For a spontaneous reaction to occur, a metal that is higher in the activity series must displace a metal that is lower in the activity series from its solution and not vice versa.
If we look at the two reactions selected in the answer, lithium is above zinc in the activity series and calcium is above aluminum in the activity series hence the two reactions occur spontaneously.
How many moles are equal to 3.0x10^23 atoms of germanium? PLS ANSWER WITH WORK!
Which of these is not a mixture?
A) Salt
B) Cooking oil
C) Tea leaves
D) Milk
ty
Answer:
the answer is salt because it has a uniform and definite composition
Explanation:
