Answer:
13 +2 =15
Explanation:
An isotope of Cesium -137 has a half-life of 30 years. If 1.0 g of Cesium – 137 disintegrates over a period of 60 years, how many grams of Cesium- 137 would remain?
Answer:
Explanation:
Radioactive decay follows the equation:
Ln [A] = -kt + ln [A]₀
Where [A] is amount of isotope after time t: Our incognite,
k is rate constant: ln 2 / Half-life = 0.0231 years⁻¹
t are 60 years
[A]₀ is initial amount of isotope: 1.0g
Replacing:
Ln [A] = -kt + ln [A]₀
Ln [A] = -0.0231 years⁻¹*60 years + ln 1.0g
ln [A] = -1.386
[A] = 0.25g
what is atomic?................................................
Answer:
oh I'm here thanks for your points
Answer:
thanx for the points
Explanation:
Butane and methyl propane are an example of a pair of
Benzoic acid, C6H5COOH, is another derivative of benzene. The pH of an aqueous solution of benzoic acid at 298 K is 2.95. Determine the concentration of hydroxide ions in the solution,
Answer:
[OH⁻] = 8.91x10⁻¹²M
Explanation:
In aqueous solutions, the [OH] and [H⁺] are associated in the equation of hydrolisis of water:
1x10⁻¹⁴ = [OH⁻] [H⁺]
With pH, we can solve for [H⁺] and obtain, the [OH⁻] using this equation:
pH = -log [H⁺]
[H⁺]= 10^-pH
[H⁺] = 1.122x10⁻³M
1x10⁻¹⁴ = [OH⁻] [1.122x10⁻³M]
[OH⁻] = 8.91x10⁻¹²MThe Environmental Protection Agency and health officials nationwide are concerned about the levels
of Radon gas in homes. The half-life of Radon-222 isotope is 3.8 days. If a sample of gas taken from
basement contains 4.38 ug of Radon-222, how long will it be until 0.55 ug will remain? How many half lives?
It takes 11.4 days⇒three half-lives
Further explanationGeneral formulas used in decay:
[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]
T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
t1/2=3.8 days
No=4.38 μg
Nt=0.55 μg
[tex]\tt 0.55=4.38\dfrac{1}{2}^{t/3.8}\\\\0.125=\dfrac{1}{2}^{t/3.8}\\\\\dfrac{1}{2}^3=\dfrac{1}{2}^{t/3.8}\\\\3=t/3.8\rightarrow t=3.8\times 3=11.4~days[/tex]
what kind of bonds involve a transfer of electrons? what kind of bond involves sharing of electrons?
Answer:
While covalent bonding involves sharing electrons between two atoms, ionic bonding involves the complete transfer of electrons from one atom to another, creating positive and negative ions. These ions are then held together by the attraction between their opposite charges.
Explanation:
Hope this helped!
For the water, what color is the hydrogen molecule?
Answer:
White is the color of a hydrogen molecule
Answer:
green. It is white when separate, but it turns green when it's formed into water.
Explanation:
When the moon is between the earth and the sun what moon phase will this be
Answer: New Moon Phase
Explanation:
Answer:
The New Moon phase
Explanation:
The moon in between the earth and the sun will cause it being a new moon because the sun's light doesn't reach the side of the moon thats facing the earth
3. IDENTIFY the following reactions as Oxidation / Reduction reactions ?
a) PbO + H2 --> Pb + H2O
b) ZnO + C --> Zn + CO
c) H2S + Cl2--> 2HCl + S
d) Fe203 + 3C0 --> 2Fe + 3CO2
e) PbS + 4H202 --- PbSO4 + 4H2O
4. In the lab activity Making Connections, an experiment was designed to test the effect of exercise on the ability to squeeze a
clothespin. The number of times the clothespin was squeezed served as the
1. independent variable 2. dependent variable
3. hypothesis
4. control
Answer: dependent variable
Explanation:
The number of times the clothespin was squeezed depends on the amount of exercise performed.
To solve this we must be knowing each and every concept related to dependent variable. Therefore, the number of times the clothespin was squeezed served as the dependent variable. The correct option is option 2.
What is dependent variable?The independent variable influences the dependent variable. The variation in the dependent variable are observed and recorded when the experimenter modifies the independent variable.
In an experiment, the dependent variable refers to the variable which is being measured or assessed. 1 In a research looking at just how tutoring affects test results, for example, the dependent variable might be the participants' exam results because that is what is being examined. The number of times the clothespin was squeezed depends on the amount of exercise performed.
Therefore, the number of times the clothespin was squeezed served as the dependent variable. The correct option is option 2.
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Is cell membrane a plant or animals cell
Answer:
They both have a cell membrane, however a plant also has a cell wall.
Explanation:
a solid sample of oil until it turns an iquid. which property of the oil will decrase?
Answer:
Density of the oil
Explanation:
As the oil sample is warmed and it turns liquid, the density of oil will decrease due to increase in volume of the oil.
Warming of the oil increases the volume of oil as it melts. The once solid oil becomes more mobile and takes up more space. Although the mass is the same. Since volume increases, the density of the oil will reduce because, density is the mass per unit volume of a substance.the first 5 elements (in increasing order) that are found in group 18
Answer:
Today, I will present the first eighteen elements which are Hydrogen, Helium, Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, Fluorine, Neon, Sodium, Magnesium, Aluminum, Silicon, Phosphorus, Sulfur, Chlorine, and Argon.
First 5: Hydrogen. The first and simplest element on the periodic table.
Helium. a very light colorless element that is one of the six inert gasses.
Lithium. A very soft, light metal.
Beryllium. A very light metal; although it is 3 1/2 times the density of Lithium.
Boron. The fifth element in the periodic table.
Explanation:
ill give brainlist if you get the right answer The _______________is how many times a wave vibrates in one second.
(Page: Frequency Pitch Match It)
Question 4 options:
vibrate
Amplification
pitch
frequency
Answer:
Frequency
Explanation:
Answer:
frequency
Explanation:
how frequently the waves come is a good way to remember
ps thanks for the brainliest
Time Period Duration (Millions of Years ago)
Cenozoic 66-0
Mesozoic 252-66
Paleozoic 541-252
Trilobites appeared approximately 521 years ago and disappeared approximately 250 million years ago. During which era did the trilobites live?
a
Cenozoic
b
Mesozoic
c
Paleozoic
d
None of These
Answer:
B
Explanation:
1. Which of these is not one of the main 6 forms of energy?
O a. Nuclear energy
O b. Chemical energy
O c. Light energy
O d. Electromagnetic energy
Answer:
Chemical energy
Explanation:
Chemical Energy
can someone solve this plz
βeta decay
carbon atomic mass 14
atomic # 6
Answer:
14/6C your welcome
Explanation:
Which element wants to gain valence electrons while bonding?
a. Neon (Ne)
b. Fluorine (FI)
c. Lithium (Li)
d. Magnesium (Mg)
Answer:
b. Fluorine (FI)
Explanation:
From the given choices, only fluorine wants to gain valence electrons while bonding.
This is because fluorine is the most electronegative specie from the given choices. An electronegative substance have a high tendency to attract electrons to itself in a bond.
Neon is a noble gas and it is stable. Lithium and Magnesium are metals that are electropositive. They prefer to lose electrons than to gain electrons.Metals react by losing valence electrons. Which of the alkali metals loses its valence electrons most easily? Explain.
Answer:
lol you have an aot profile pic
Rooted aquatic plants can be found in areas with lower sunlight exposure.
The answer is false.
Answer:
False
Explanation:
Edgeeee
the diagram below shows three containers of gas.
Which list correctly describes the gases in containers R, S, and T?
a R= element s = compound t = mixture
b R= compound s = element T= mixture
cR= element s = mixture t= compound
d r = mixture s= emelem t = compound
ASAP
Answer:
d
Explanation:
The correctly describes the gases in containers R, S, and T is R = mixture S = element and T = compound. Hence option d is correct.
What are gases?Gases are defined as the state of matter where particles often travel very swiftly, far apart from one another, and with little or no attraction to one another. They take up much more space than the liquids or solids from which they are formed, are simple to compress, and expand to fill their containers.
Particles make up all matter; these particles can be single atoms or atoms that have been chemically combined to form molecules. This fact allows us to divide matter into three general categories: elements, compounds, and mixtures. All the atoms in an element are of the same kind. A compound is created when more than one kind of atom is chemically bonded.
Thus, the correctly describes the gases in containers R, S, and T is R = mixture S = element and T = compound. Hence option d is correct.
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A 23.7 g piece of iron at 54.9°C is cooled and releases 338 J of heat. The specific heat of iron is 0.450 J/g°C.
Answer:
The heat capacity and the specific heat are related by C=cm or c=C/m. The mass m, specific heat c, change in temperature ΔT, and heat added (or subtracted) Q are related by the equation: Q=mcΔT. Values of specific heat are dependent on the properties and phase of a given substance.
Explanation:
Answer:
23.2 degrees c
Explanation:
As the frequency decreases the wavelength...
Answer:
Increase
Explanation:
Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency of the wave: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths.
The chemical equation below shows the amount of the reactants used and the amount of only one of the products formed. How much water (H2O) should be formed in this chemical reaction? CH4 mass 4 + 2O2 mass 16 CO2 11 + 2h2O mass ?
Answer:
CH4 + 2O2 → CO2 + 2H2O
Explanation:
This is all i could come up with im sorry.
The amount of water formed in the given chemical reaction is 9 grams.
What is Stoichiometry?Stoichiometry is the calculation for the determination of the relative amount of reactants and products in chemical reactions. Stoichiometry is based on the law of conservation of mass where the total mass of the reactants in reaction equals the total mass of the products.
If the quantity of one reactant is known and the quantity of the product can be determined empirically, then the quantity of the other reactants can be calculated.
Given chemical equation is:
CH₄ + 2O₂ [tex]\longrightarrow[/tex] CO₂ + 2H₂O
16g 32g 44g 32g (from their molecular masses)
The amount of methane, oxygen, and carbon dioxide is 4g, 16g, and 32 g respectively.
16g of methane react with oxygen = 32g
4g of methane will react with oxygen = 8g
It means here methane is the limiting reagent as the given amount of oxygen is more than reacted one. So CH₄ will decide the amount of water.
16g of methane produces water = 32g
Then 4g of methane will produce water = (32/16) × 4 = 9 g
Therefore, 9 grams of water should be formed in this reaction.
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What is the role of CdKs? to create enzymes that produce chemical changes to signal the cell to move to the next phase of the cell cycle to build structural components of DNA and energy-rich substances to activate the cyclins that cause progression of the cell cycle
Answer:
It’s b
Explanation:
Answer:
Regulation of the cell cycle is carried out by which of the following? Check all that apply.
CdKs
cyclins
What is the role of CdKs?
to signal the cell to move to the next phase of the cell cycle
Explanation:
The data table below shows four different chemical reactions, the temperature change of each, and the duration of the change in temperature. Based on this data, which reaction would be classified as an exothermic reaction? Explain your answer. ALL TEMPS ARE IN CELSIUS
Reaction 1: temp change: -25 degrees; duration of temp change: 25 mins
Reaction 2: temp change: -23 degrees; duration of temp change: 15 mins
Reaction 3: temp change: -30 degrees; duration of temp change: 25 mins
Reaction 4: temp change +22 degrees; duration of temp change: 30 mins
Answer:
Reaction 4
Explanation:
exothermic reaction is reaction in which reaction takes place evolving heat
Answer:
NO
Explanation:
the reson is because nobody wanna answer my questions
Caculate the density of sulfuric acid if 35.4 mL if. The acid weighs 65.14 grams
Answer:
[tex]\boxed {\boxed {\sf d\approx 1.84 \ g/mL}}[/tex]
Explanation:
Density can be calculated by dividing the mass by the volume.
[tex]d=\frac{m}{v}[/tex]
The mass of the sulfuric acid is 65.14 grams. The volume is 35.4 milliliters.
[tex]m= 65.14 \ g \\v= 35.4 \ mL[/tex]
Substitute the values into the formula.
[tex]d=\frac{65.14 \ g}{35.4 \ mL}[/tex]
Divide.
[tex]d=1.84011299 \ g/mL[/tex]
Let's round to the nearest hundredth to make the answer concise.
The 0 in the thousandth place tells us to leave the 4 in the hundredth place.
[tex]d\approx 1.84 \ g/mL[/tex]
The density of sulfuric acid is about 1.84 grams per milliliter.
What product(s) are formed during this chemical reaction? (Will be two answers)
B(NO3)3 + KBr rightwards arrow
K(Br)3
KNO3
Br3(NO3)2
K3NO4
B(NO3)K
B3K3
BBr3
BK
Answer:
BK. BK. BK BK BK BK BK BK BK BK BK BK BK BK BK BK BK BK BK BK BK BK BK BK BK BK BK BK BK BK
Carbon makes up part of all life forms on Earth. The human body, for example, is about blank % carbon.
2+2=4 and the. You add 7