Write an informal definition of half-life.
the time required for the activity of a substance taken into the body to lose one half its initial effectiveness. Informal. a brief period during which something flourishes before dying out.
hope this helps ^^
Assume that a 100-base pair DNA double helix contains 45 cytosine bases. Use logical thinking to figure out how many adenine bases there will be. Explain how you know.
Answer:
You will not be allowed to have any learning aids while taking a test or ... A DNA molecule consists of three parts—a nitrogen base, ... There are four DNA nucleotides, each with one of the four nitrogen bases (adenine, thymine, cytosine, and guanine). The DNA forms a two-stranded spiral, or double helix.
Explanation:
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The best description of the Big Bang Theory is ______________
A. The universe began with cold dense energy compressing into matter after which all matter and energy began rapidly contracting toward each other.
B. The universe began with hot dense energy compressing into matter after which all matter and energy began rapidly expanding away from each other.
C. The universe began with hot dense matter after which all energy began rapidly expanding away from each other.
D. The universe began with cold, spread out matter compressing into energy, after which all matter and energy began slowly moving toward each other
Answer:
B. the universe began with hot dense energy compressing into matter after which all matter and energy began to rapidly expanding away from each other.
hope it helps
35 points
What are the reactants and the products in this equation?
2H2 + O2 → 2H2O
a Reactants: water; Products: hydrogen, oxygen
b Reactants: hydrogen, oxygen; Products: water
Answer:
02 ;D h2oooooooooooo
long story shortB
Explanation:
Answer:
B
Explanation:
2H2→Hydrogen peroxide
O2→oxygen
"A water molecule (formally known as dihydrogen monoxide) is composed of two hydrogen atoms and one oxygen atom. ... The actual reaction to make water is a bit more complicated: 2H2 + O2 = 2H2O + Energy"
"A reactant is a substance that is present at the start of a chemical reaction. The substance(s) to the right of the arrow are called products . A product is a substance that is present at the end of a chemical reaction."
The answer is B, hope this helps :)
properties changes if the size of an object changes?
A.mass
B.volume
C.weight
D.all of the above
Answer:
D
Explanation:
The answer should be D, when the size of an object changes it changes how much mass it has how heavy it is (weight), and how much space it takes up (volume).
Which formula below can be used to calculate speed?
Speed = Volume ÷ Mass
Speed = Time ÷ Distance
Speed = Mass x Acceleration
Speed = Distance ÷ Time
Answer:
The answer is Speed= Distance ÷ Time
Explanation:
To work out what the units are for speed, you need to know the units distance and time.
How is elevation shown on a topographic map?
O intermediate contours
O index contours
O contour intervals
Ocontour lines
Answer:
D. Contour lines.
Explanation:
The primary difference is that they show elevation in detail. Characteristics of topographic maps include: they show elevation using contour lines. Put simply, a contour line is a line which joins points of equal elevation above sea level.
PLEASE HELP ASAP!!!
A teacher wrote the following part of a chemical equation involving water (H2O) and carbon dioxide (CO2): H2O + CO2 ---> ?
What is the most likely result of the chemical reaction represented by this equation?
A. H2CO3
B. NaCl
C. HNO3
D. H2Ca3
Answer:
Id say A. I think I hope I'm right
convert 100 ml to L can you help mee??
Answer:
0.1 L
Explanation:
divide the volume value by 1000
Answer:
0.1 L that is the answer
Explanation:
I searched it
how does activation energy influence a reaction
Answer: The activation energy of a particular reaction determines the rate at which it will proceed. The higher the activation energy, the slower the chemical reaction will be. The example of iron rusting illustrates an inherently slow reaction.
Explanation:
What is meant by the dual wave-particle nature of light?
Dual wave particle nature of light can be regarded as mechanism that says light and matter will also has the properties of waves as well as that of particles.
This concept is found in mechanics as it describes how light and matter also has the properties associated with waves as well as particles.The duality explained inadequacy of conventional concepts of both wave and particle so as to give explanation about behaviour of quantum objects.the dual nature of light made us to understand that light has wave properties and it also has particle properties.Some of the properties of wave that light has are:
wavelengthspeedTherefore, duality means have both characteristics of light and wave
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Why does forming bonds release energy? *
How many molecules of nitrogen dioxide NO2 are in 1 mole of NO2?
Answer:
The answer is 46.0055. We assume you are converting between grams NO2 and mole. You can view more details on each measurement unit: molecular weight of NO2 or mol This compound is also known as Nitrogen Dioxide.
Explanation:
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how can acids cause chemical weathering
The acids react with the chemical composition of the rock causes the disintegration of the rocks.
Chemicals when react with the chemical components of the rocks cause the disintegration of the chemical and physical structure of rocks which cause breakage of rocks into parts. This process is called chemical weathering.
For example, the sulfur dioxide gas in the air reacts with the water in the air to form the acid rain.
The acid rain reacts with the chalk or limestone rock that causes the disintegration of the chemical structure and physical structure of rock causing breakage of the chalk or limestone.
Learn more about weathering:
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HELPPP simply the expression!!!!
Answer:
[tex] \frac{3}{ \sqrt{3} } \times \frac{ \sqrt{3} }{ \sqrt{3} } = \frac{3 \sqrt{3} }{3} = \sqrt{3} [/tex]
when there is a radical in the denominator, we should rationalize (mutiply the denominator and numerator by the radical) to get rid of the radical in the denominator.
27.2Pb(NO3)2 --> 2Pb0 + 4NO2 + O2
O A. Synthesis
B. Single displacement
C. Decomposition
D. Combustion
Find the number of moles if you have 1.2 x 1048 copper atoms.
Answer:
1.993 × 10^(24) moles
Explanation:
From avogadro's number, we have that;
1 mole of atoms contain 6.022 × 10^(23) atoms
Therefore, 1.2 x 10^(48) atoms of copper will contain;
(1.2 x 10^(48) × 1)/(6.022 × 10^(23)) = 1.993 × 10^(24) moles
What force pulled the solar system together out of a cloud of gas and dust
how can a substance stay at a certain temperature even though it is being heated?
which one of the following can be separated by physical means:
(a) element
(b) mixture
(c) compound
(d) radical
Answer:
B mixture can be separated by physical means
Answer:
this is compound ok or not
Is Mg(CH3COO)2 soluble or insoluble
Answer:
It is Soluble
Explanation:
Name- Magnesium acetate
It dissolves easily in water and alcohol.
Please help... giving a lot of points and awarding brainliest.
how many grams of sodium carbonate must react with 222 g of calcium chloride to make 233 grams of sodium chloride and 201 grams of calcium carbonate?
Answer: 212 g of sodium carbonate must react
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products formed must be equal to the mass of reactants taken.
In order to get the same mass on both sides, the atoms of each element must be balanced on both sides of the chemical equation.
The balanced chemical equation is:
[tex]Na_2CO_3+CaCl_2\rightarrow 2NaCl+CaCO_3[/tex]
Mass of products = mass of sodium chloride + mass of calcium carbonate = 233 g+ 201 g= 434 g
Mass of reactants= mass of sodium carbonate + mass of calcium chloride =x + 222 g
As the mass of reactants should be equal to mass of products
434 = x + 222 g
x = 212 g
Thus 212 g of sodium carbonate must react with 222 g of calcium chloride to make 233 grams of sodium chloride and 201 grams of calcium carbonate
What can be concluded from the statements above?
A. A harmful compound can become harmless when its elements are separated.
B. A harmless compound can become harmful when its elements are separated.
C. Breaking a compound into its separate elements has no noticeable effects.
D.Breaking a compound into its separate elements can create carbon dioxide.
Answer:
B
Explanation:
I am not sure why
Answer:
Yea I think B as well!!!!!
To Identify a mineral, there are tests that are used including:
Geologists use the following tests to distinguish minerals and the rocks they make: hardness, color, streak, luster, cleavage and chemical reaction.
Can someone balance these equations?
This is mind numbing, but I got you.
3NaOH + 1FeCl3 = 1Fe(OH)3 + 3NaCl
3Mg + 2H3(PO)4 = 1Mg(PO4)2 + 3H2
In Step 5, you will calculate H+/OH– ratios for more extreme pH solutions. Find the concentration of H+ ions to OH– ions listed in Table B of your Student Guide for a solution at a pH = 2. Then divide the H+ concentration by the OH– concentration. Record these concentrations and ratio in Table C. What is the concentration of H+ ions at a pH = 2? mol/L What is the concentration of OH– ions at a pH = 2? mol/L What is the ratio of H+ ions to OH– ions at a pH = 2? : 1
Answer:0.01
0.000000000001
10,000,000,000
Explanation:
Answer:
1. What is the concentration of H+ ions at a pH = 2?
0.01 mol/L
2. What is the concentration of OH– ions at a pH = 2?
0.000000000001 mol/L
3. What is the ratio of H+ ions to OH– ions at a pH = 2?
10,000,000,000 : 1
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Explain why Chlorine has the largest electronegativity between Ne, Mg, Ba, Sb, Hg, Li?
Answer:
Look at the image provided and try work it out. I don't have the time but I hope I helped you!
Explanation:
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If you place Alka -Seltzer tablets in a closed container of water, the tablets effervescence then produce a gas. What will eventually happen inside this closed container?
A. Not enough information to determine.
B. The pressure decreases.
C. The pressure increases.
D. The pressure remains the same.
Answer:
c the pressure increases
What three types of particles make up an atom? What are their charges?
Answer:
Protons, neutrons, and electrons are the three main subatomic particles found in an atom. Protons have a positive (+) charge. An easy way to remember this is to remember that both proton and positive start with the letter "P." Neutrons have no electrical charge.
Answer:
Protons, positive charge
Neutrons, neutral
Electrons, negative charge
Explanation: