Answer:
I am pretty sure that it is A. H2.
Explanation:
Sorry if it's wrong.
If we start with 1.000 g of strontium-90, 0.908 g will remain after 4.00 yr This means that half-life of strontium-90 is _________ yr.
A) 3.05
B) 4.40
C) 28.8
D) 3.63
E) 41.6
Answer: C) 28.8
Explanation:
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant
t = age of sample
a = initial amount of the reactant = 1.000 g
a - x = amount left after decay process = 0.908 g
a) to find rate constant
[tex]4.00yr=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
[tex]k=\frac{2.303}{4.00}\log\frac{1.000}{0.908}[/tex]
[tex]k=0.024yr^{-1}[/tex]
b) for completion of half life:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]
[tex]k=\frac{0.693}{0.024yr^{-1}}=28.8yr[/tex]
The half-life of strontium-90 is 28.8 yr.
aight imma let you guys i
Answer:
b
Explanation:
it is right
Help with as many as possible is appreciated! :)
Calculate the molarity of the solutions described below.
a. 10.0 g of sodium chloride is dissolved in 2.0 L of solution.
b. 52.5 g of sugar (C12H22O11) s dissolved in 1.0 L of solution.
c. 120 g of aluminum sulfate is dissolved in 10.0 L of solution.
d. 1.75 g of caffeine (C8H10N4O2) is dissolved in 0.100 L of solution.
Answer:
a. 0.0855 M
b. 0.153 M
c. 0.0351 M
d. 0.0901 M
Explanation:
a.
Molar mass NaCL= 23.0 +35.5 = 58.5 g/mol
10.0 g* 1 mol/58.5 g = 10.0/58.5 mol
(10.0/58.5) mol/2L = 0.0855 mol/L = 0.0855 M
b.
Molar mass (C12H22O11) =342.3 g/mol
52.5 g*1mol/342.3 g = 52.5/342.3 mol=0.153 mol
0.153 mol/1L = 0.153 M
c.
Molar mass (Al2(SO4)3) =342.2 g/mol
120g* 1 mol/342.2 g =0.351 mol
0.351 mol/10.0L = 0.0351 mol/L = 0.0351 M
d.
Molar mass (C8H10N4O2) = 194.2 g/mol
1.75 g*1mol/194.2 g = 0.00901 mol
0.00901 mol/0.100 L =0.0901 M
An object becomes positively charged when it
a loses electrons.
b loses protons.
c gains electrons.
d gains neutrons.
2. Find out the enthalpy change of the CH4 from solid Carbon and Hydrogen gas. C (s)+ 2H2 (g)(CH4(g) (H( = ?
Use the following three equations:
C (s)+ O2 (g)(CO2(g) (H( = -393.5 kJ
H2 (g)+1/2 O2 (g)(H2O(l) (H( = -285.8 kJ
CH4 (g)+ 2O2 (g)( CO2(g)+ 2H2O(l) (H( = -890.3 kJ
Answer:
Approximately [tex]-74.8\; \rm kJ \cdot mol^{-1}[/tex].
Explanation:
Number the three reactions with known enthalpy changes:
[tex]\begin{aligned}& {\rm C\; (s) + O_2\; (g) \to CO_2\; (g)} & \quad \Delta H = -393.5\; \rm kJ\cdot mol^{-1}& \quad (1) \\ & {\rm H_2\; (2) + \frac{1}{2} O_2\; (g) \to H_2O\; (l)} & \quad \Delta H = -285.8\; \rm kJ\cdot mol^{-1} & \quad (2) \\ & {\rm CH_4\; (g) + 2\; O_2\; (g) \to CO_2\; (g) + 2\; H_2O\; (l)} & \quad \Delta H = -890.3\; \rm kJ\cdot mol^{-1} & \quad (3)\end{aligned}[/tex].
The goal is to find a way to combine these three reactions to obtain: [tex]\rm C\; (s) + 2\; H_2\; (g) \to CH_4\; (g)[/tex].
Assume that the three known reactions are combined in this way:
[tex]a \times (1) + b \times (2) + c \times (3)[/tex].
That corresponds to:
[tex]\begin{aligned} & a\; \mathrm{C\; (s)} + \left(a + \frac{1}{2}\, b + c\right) \; \mathrm{O_2\; (g)} + b\; \mathrm{H_2\; (g)} + c\; \mathrm{CH_4\; (g)} \\ & \to (a + c)\; \mathrm{CO_2\; (g)} + (b+ 2\,c )\; \mathrm{H_2O\; (l)}\end{aligned}[/tex].
Compare the coefficients of this reaction with that of the desired reaction:
[tex]\rm C\; (s) + 2\; H_2\; (g) \to CH_4\; (g)[/tex].
Note that some species (e.g., [tex]\rm CH_4\; (g)[/tex]) appeared on the wrong side of the equation. Their desired coefficient should be the opposite of their true coefficient. For example, the coefficient of [tex]\rm CH_4\; (g)[/tex] is supposed to be [tex]1[/tex]. However, because it appeared on the wrong side of the equation, its desired coefficient would be [tex]-1[/tex].
The coefficients of species that are not in the desired equation should be zero.
[tex]\begin{array}{|c|c|c|}\cline{1-3}\text{Species} & \text{Coefficient}& \text{Desired Coefficient} \\ \cline{1-3} \mathrm{C\; (s)}} & a & 1 \\ \cline{1-3} \mathrm{O_2\; (g)} & a + (1/2)\, b + c & 0 \\ \cline{1-3} \mathrm{H_2\; (g)} & b & 2 \\ \cline{1-3}\mathrm{CH_4\; (g)} & c & -1\\ \cline{1-3} \mathrm{CO_2\; (g)} & a + c & 0 \\ \cline{1-3} \mathrm{H_2O\; (l)} & b + 2\, c & 0\\ \cline{1-3}\end{array}[/tex].
Solve for [tex]a[/tex], [tex]b[/tex], and [tex]c[/tex]:
[tex]a = 1[/tex].[tex]b = 2[/tex].[tex]c = -1[/tex]. In other words, the third equation is inverted before being added to the other two equations.In other words, the desired equation is equal to [tex]1 \times (1) + 2 \times (2) - 1 \times (3)[/tex].
By Hess's Law, the enthalpy of the desired equation will be:
[tex]\begin{aligned}& 1\times \Delta H (1) + 2 \times \Delta H (2) - 1\times \Delta H(3) \\ &\approx -393.5 + 2 * (-285.8) - (-890.3) \\ &= -74.8\; \rm kJ \cdot mol^{-1} \end{aligned}[/tex].
An ion with a -2 charge has? A) one missing protein B) two missing protons c) two missing electrons D) two extra electrons
Answer:
D.
Explanation:
It would not be gain because it would say +6 instead of -2. Having a -2 charge means it wants to loose 2 electrons so it can form a full shell of 8 electrons. It wants to be inert (stable).
- Hope that helps! Please let me know if you need further explanation.
A plastic bag has a volume of 22.3 L at a pressure of 99.5 kPa. If you climb a mountain and the bag expands to a volume of 22.9 L, what is the air pressure at the top of the mountain?
Answer: The air pressure at the top of the mountain is 96.9 kPa
Explanation:
To calculate the new pressure, we use the equation given by Boyle's law. This law states that pressure is directly proportional to the volume of the gas at constant temperature.
The equation given by this law is:
[tex]P_1V_1=P_2V_2[/tex]
where,
[tex]P_1\text{ and }V_1[/tex] are initial pressure and volume.
[tex]P_2\text{ and }V_2[/tex] are final pressure and volume.
We are given:
[tex]P_1=99.5kPa\\V_1=22.3L\\P_2=?\\V_2=22.9L[/tex]
Putting values in above equation, we get:
[tex]99.5\times 22.3L=P_2\times 22.9L\\\\P_2=96.9kPa[/tex]
Thus the air pressure at the top of the mountain is 96.9 kPa
I need the answers to this question please
The options are
A.0.17g/cm^3
B.5.38g/cm^3
C.0.05g/cm^3
D.8g/cm^3
Answer:
Before submerged 150ml
After submerged: 180ml
rock volume: [tex]180 - 150 = 30[/tex]
formula for density:
[tex] \frac{mass}{volume} = 5.38 [/tex]
[tex] \frac{175}{30} = 5.38 [/tex]
THE ANSWER IS b
prettty sure this is wrong but eh :/ probably correct
sonar measures underwater distances by using?
Answer:
By using the speed of sound in water
Explanation:
(Which is about 1500 m/s in sea depending on the sea water density )
High levels of carbon dioxide in the blood trigger which of the following responses in the body?
Select one:
a decrease in the production of sweat
a decrease in the speed of the pulse
an increase in the rate of breathing
an increase in the rate of digestion
The amplitude of a wave is the vertical distance from the midpoint to either the crest or the
trough of the wave
True
False
EMERGENCY OR I WILL FAIL PLS HELP I WILL MARK BRAINLIEST!!!!
Answer:
1. sublimation
2.melting
3.melting
4.sublimation
Explanation:
melting is a process when solid changes to liquid
Sublimation is the transition of a substance directly from the solid to the gas state, without passing through the liquid state.
A pelican is born with a larger bill than other pelicans of the same species. When this pelican
breeds, some of its offspring also have larger bills. What is the most likely explanation for the
larger bills in the pelican and its offspring?
Inheritance of an quoted trait
A mutation
Natural selection
A change in diet
Answer:
natural selection
Explanation:
it is a biological selection of genes, whether dominant or negative.
Which of the following presents a safety hazard while working in the science laboratory?
A knowing how to use equipment
B wearing safety goggles
C following directions
D working alone
Answer:
D working alone
Explanation:
Working alone is the only option that could potentially be a safety hazard; if you have no one watching your back, errors could occur, like dropping glass or burning your hand, and no one is around to help you.
Choices A, B, and C are not correct because those are all good safety standards.
an _____ bond forms when one element give electrons to another element - one becomes a positive ions and the other a negative ion.
covalent
metallic
ionic
Answer:
ionic
Explanation:
What is the answer ?
Answer: c
Explanation: an xray wave does have a higher frequency than an infrared wave.
Answer:
Explanation:c
How are electrons similar and different to the planet Earth?
Answer:
The planets themselves are composed of several trillions or quadrillions or more atoms. As far as hard science is concerned, it would be really hard to picture them as electrons. Conclusion: It can be said with a great accuracy that our planets are NOT huge electrons.
Rutherford's experiments showed that the mass of atoms was mostly concentrated in a very small region, with charge equal to the atomic number- the nucleus. He absolutely did not show, nor is it true, that electrons orbit the nucleus as if they were planets. That was a guess people made in trying to figure out how to picture the atom.
(Hope this helps) Sky
5.UT
---Urut points)
Which of the following explains the process of radiation?
5.1
when heat gets transferred through electromagnetic waves that move through
space
5.1
when heat gets transferred through objects that are touching
5.1
when heat gets transferred through a liquid or a gas
O when the measurement of heat in the atmosphere goes down
Answer:
when heat gets transferred through electromagnetic waves that move through
space
Explanation:
Radiation refers to the movement of energy through space without a material medium of propagation.
Electromagnetic waves have the ability to travel through space without a material medium for propagation. For instance, the rays from the sun reach us on earth without any intervening medium. Heat from a furnace can affect an object some distance away from the furnace without an intervening medium.
These are all examples of radiation. Energy is propagated through space without the intervention of any material medium.
Calculate the molarity of a KCl solution if 37.3 g of KCl are dissolved in water to give a
final solution volume of 500 ml.
The molarity of a KCl solution if 37.3 g of KCl are dissolved in water to give a final solution volume of 500 ml is 1 M.
What is Molarity?Molarity of a given solution is known as the total number of moles of solute per litre of the solution. A solution that is 1.00 molar (written 1.00 M) contains 1.00 mole of solute for every liter of solution.
Molarity = (No. of moles of solute ÷ Volume of solution in liters)
The unit of molarity is mol L⁻¹.
Molarity is temperature dependent because as temperature changes, volume of the solution also changes.
Given, Mass of KCl = 37.3 g
Molar mass of KCl = 74.5 g/mol
Volume of solution = 500ml = 0.5 L
No. of moles = Mass / Molar mass = 0.5
Molarity = 0.5/0.5 = 1 M
Therefore, The molarity of a KCl solution if 37.3 g of KCl are dissolved in water to give a final solution volume of 500 ml is 1 M.
Learn more about Molarity, here:
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Explain why a small magnet will stick to a refrigerator door, but a nail will not stick.
Answer:
Magnets stick to the fridge door because, underneath the paint, the door is made of steel. Magnets are attracted to certain metals, and if the attraction is strong enough they can hold on even when upside down. ... This means that a magnet will always be attracted to the door. But an iron nail does not have any magnetic properties. So it doesnt get attracted.
Hope this helps, Pls mark as Brainliest!!
A small magnet will stick to a refrigerator door, but a nail will not stick
because magnets attract certain types of metals.
Magnets have a strong magnetic field which is why it attracts metals such
as iron and steel. The refrigerator must have been made with iron or steel
which was why the magnet stuck to it.
Metals such as aluminium and copper aren't attracted by magnets which is
why the nails weren't attracted as a result of it being made with metals which magnets don't attract.
Read more on https://brainly.com/question/19482396
A calcium atom differs from a calcium ion in that the atom has a greater
A)
number of electrons
B)
number of protons
C)
atomic number
D)
mass number
Answer:
A) number of electrons
Explanation:
A calcium atom has 20 electrons while a calcium ion has 18 electrons since it loses 2 electrons to form a stable octet structure. The formula of a calcium ion is Ca2+.
The number of protons does not change, neither do the number of neutrons. Atomic number is the proton number which is equals to the number of protons, hence B and C is wrong. Mass number is the number of protons and neutrons. Hence it doesnt change too and D is wrong.
Only the number of electrons change when an atom forms an ion.
Which sentence best describes part of the process for generating electricity in a nuclear power plant?
A.Atoms Join together to produce water molecules.
B.An atom releases electrons, producing an electric current.
C.Protons and neutrons Join together to create atoms.
D.Heat is released when atomic nuclel split.
Answer:it is D
Explanation: it is only one that makes sense
What is the freezing point of a 2.00 m solution with phenol as
the solvent?
Answer: 26.1 C
Explanation: Trust me
Answer:26.1
Explanation:
I did the ck12
How many moles of gas fill a 2.2 L vessel with a pressure of 1.2 atm at 25.0 °C?
P=
V=
n=
R=
T=
Formula:
Answer:
Do you still need this answer? If you do i can provide it for you still
Thank you
what is an example of a strong base?
HCl
NaCl
NaOH
HF
Answer:
The answer is NaOH
Explanation:
Strong bases are characterized by the fact that they dissociate completely in an aqueous solution. In this case, sodium hydroxide, NaOH, is classified as a strong base because it dissociates completely in an aqueous solution to form sodium cations, Na+, and hydroxide anions, OH−. Also, it is strong because it totally breaks in its ion. And the base which breaks totally in its atom called the strong base and which doesn't it that is a weak base.
Answer:
NaOH
Explanation:
Got it right in the test. Please mark as brainliest
's A pitcher contains 1 gallon of
lemonade. All of the lemonade will be
poured into 4 empty glasses. If an equal
amount is poured into each glass, how
much lemonade will be in the first glass?
Answer:
1 quart of lemonade will be in the first cup
Explanation:
1/4th of a gallon is a quart
Why is wind named from where the wind is blowing from?
Winds are always named from the direction it blows from
Uneven heating of Earth's surface,in turn,causes differences in air pressure at various locations. Heated air rises,creating an area of low pressure beneath. Cooler air descends, creating an area of high pressure
Show ur working:
What mass of sulfur trioxide is formed from 96g of sulfur dioxide?
2 SO2+O2 –> 2 SO3
Answer:
120 g SO3
Explanation:
128 g SO2 -> 160 g SO3
96 g SO2 -> x
x= (96 g SO2 * 160 g SO3)/128 g SO2
x= 120 g SO3
The mass of sulfur trioxide, SO₃, formed is 120 g
The balanced equation for the reaction is given below:
2SO₂ + O₂ —> 2SO₃Next, we shall determine the mass of SO₂ that reacted and the mass of SO₃ produced from the balanced equation. This can be obtained as follow:
Molar mass of SO₂ = 32 + (16×2)
= 32 + 32
= 64 g /mol
Mass of SO₂ from the balanced equation = 2 × 64 = 128 g
Molar mass of SO₃ = 32 + (16×3)
= 32 + 48
= 80 g /mol
Mass of SO₃ from the balanced equation = 2 × 80 = 160 g
Thus,
From the balanced equation above,
128 g of SO₂ reacted to produce 160 g of SO₃.
Finally, we shall determine the mass of SO₃ by the reaction of 96 g of SO₂. This can be obtained as follow:
From the balanced equation above,
128 g of SO₂ reacted to produce 160 g of SO₃.
Therefore, 96 g of SO₂ will react to produce = [tex]\frac{96 X 160}{128}\\\\[/tex] = 120 g of SO₃.
Therefore, the mass of SO₃ formed is 120 g
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the radioactive atom 61/27 co emits a beta particle. write an equation showing the decay
Answer:
[tex]\rm _{27}^{60}\text{Co} \longrightarrow \, _{-1}^{0}\text{e} + \, _{28}^{60}\text{Ni}[/tex]
Explanation:
The unbalanced nuclear equation is
[tex]\rm _{27}^{60}\text{Co} \longrightarrow \, _{-1}^{0}\text{e} + \, ?[/tex]
Let's write the question mark as a nuclear symbol.
[tex]\rm _{27}^{60}\text{Co} \longrightarrow \, _{-1}^{0}\text{e} + \, _{Z}^{A}\text{X}[/tex]
The main point to remember in balancing nuclear equations is that the sums of the superscripts and the subscripts must be the same on each side of the equation.
Then
60 = 0 + A, so A = 60 - 0 = 60, and
27 = -1 + Z, so Z = 27 + 1 = 28
Your nuclear equation becomes
[tex]\rm _{27}^{60}\text{Co} \longrightarrow \, _{-1}^{0}\text{e} + \, _{28}^{60}\text{X}[/tex]
Element 28 is nickel, so the balanced nuclear equation is
[tex]\rm _{27}^{60}\text{Co} \longrightarrow \, _{-1}^{0}\text{e} + \, _{28}^{60}\text{Ni}[/tex]
3 2 1
1H + 1H ——> 0n + ___
Answer:
2H on 3H
Explanation:
it's because Mario eh, eh, eh. now back of and habeba goodnday
