what is the periodic table elements
Answer:
Here is a picture of all the elements
Answer:
The periodic table is a tabular array of the chemical elements organized by atomic number, from the element with the lowest atomic number, hydrogen, to the element with the highest atomic number, oganesson. The atomic number of an element is the number of protons in the nucleus of an atom of that element.
Explanation:
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What causes a spectrum of colors to appear when light moves through a prism?
Absorption of light waves
O Refraction of light waves
Transmission of light waves
Reflection of light waves
Answer:
It is refracted out, B
Explanation:
When the light travels through the prism, it refracts the colors out of it. In which a rainbow sort coloration is released from the other side.
Answer:
Explanation:
Refraction of light waves
2 points
A student saw the Moon rise at 6:20 a.m. on Monday. If he wants to see
the Moon rise again on Tuesday, vhat time should he look in the sky?(Mark
the one best answer.)
About 6:20 am
About 6:20pm
About 5:30 am
About 7:10am
What type of succession takes place when a community starts to grow?
A. Primary
B. Secondary
Answer:
Primary
Explanation:
Succession is a series of progressive changes in the composition of an ecological community over time. In primary succession, newly exposed or newly formed rock is colonized by living things for the first time.
Please help if you know please and thanks ;)
Answer:
it takes two hydrogen atoms for every oxygen atom to produce this reaction, so the mole ratio between hydrogen and oxygen is 2:1
A student is investigating potential and kinetic energy by stretching a spring across a table. When the student lets go
The spring recoils.
Answer: When the spring is recoiling
Explanation:
Answer:
When the spring is recoiling
Explanation:
An aqueous solution of 6.70 M ammonia, NH3, has a density of 0.950 g/mL. The percent by mass of NH3 in the solution is %.
Answer:
12.01% by mass
Explanation:
Percent by mass is 100 times the mass of solute (ammonia) over the mass of the solution. In molarity, we have the moles of ammonia per liter of solution. There are 6.70moles of NH3 in 1L. Thus, we need to convert the moles of ammonia to grams and the liters of solution to grams:
Mass ammonia - Molar mass: 17.031g/mol-
6.70moles * (17.031g / mol) = 114.1g NH₃
Mass solution:
1L * (1000mL / 1L) = 1000mL * (0.950g/mL) = 950g
Percent by mass:
114.1g NH₃ / 950g * 100 =
12.01% by massThe half-life of sodium-24 is 15 days. A laboratory technician measures out a 72 g sample. Approximately how many grams of sodium-24 would remain after 45 days?
Answer:
after 45 days 9 g left
Explanation:
Given data:
Half life Na-24 = 15 days
Mass of sample = 72 g
Mass remain after 45 days = ?
Solution:
Number of half lives passed:
Number of half lives = time elapsed / half life
Number of half lives = 45 days / 15 days
Number of half lives = 3
At time zero total amount = 72 g
After first half life = 72 g/ 2= 36 g
At 2nd half life = 36 g/2 = 18 g
At 3rd half life = 18 g/2 = 9 g
Thus after 45 days 9 g left.
A substance made up of two or more types of atoms that are NOT chemically combined is called a(n)
A
element
B
mixture
с
compound
D
pure substance
Answer:
pure substance
Explanation:
it does not combine to anything.
A reference point is an object or location from which the movement of another object is determined. Which of the following could be
a reference point?
I. a house
II. a moving car
III. a point on a map
IV. a person
A. I,III and IV only
B. I, II, III, and IV
C. Ill only
D. I and III only
Answer:
C. Ill only
Explanation:
Motion can be defined as a change in location with respect to a reference point.
This ultimately implies that, motion would occur as a result of a change in location (position) of an object with respect to a reference point or frame of reference i.e where it was standing before the effect of an external force.
Mathematically, the motion of an object is described in terms of acceleration, time, distance, speed, velocity, displacement etc.
A reference point is an object or location from which the movement of another object is determined.
Thus, a point on a map is considered to be a reference point because it represents the starting point of an object or person in motion.
Which of the following is the definition of erosion?
A the process that involves The movement Of soil and rock
The process Of disitgration Of rock and soil
Neither
Both
Choose one and explain
Answer:
Neither
Explanation:
None of the answer choices is the correct definition of erosion. Erosion is actually the removal of weathered materials and particle from the surface of rocks and soils.
The process by which rocks and soils are moved is called transportation. The process of disintegration of rocks and soil is called weathering.Erosion is a serious problem in Agriculture as it removes rich and fertile soil cover. This therefore renders the soil barren and stripped of available nutrients.
Answer:
The process of breaking down rock and soil.
Explanation:
How does an objects speed affect its kinetic energy?
The frequency of the stretching vibration of a bond in IR spectroscopy depends on what two quantities?
Answer:
Strength of the bond
Masses of the bonded atoms.
Explanation:
The lack of such groups means that they are not endogenous in the concentrate. 1. A bond's spreading frequency relies on the frequency of the bond and the concentrations of the atoms that are bonded.
HEY THIS ANSWER CORRECT ?
Answer:
I don't think that answer is right. I got 543.04 grams.
Explanation:
I think the question is asking for grams in the samlpe instead of the moles in the sample because it already gives you the amount of moles.
what problems occurs if the firework mixture is not pure(they are dirty or contaminated?
Firework mixture is made up with potassium nitrate and other toxic chemicals. They produce harmful wastes to the atmosphere. If they are contaminated, they make release very dangerous explosives by unwanted reactions.
What are explosives?Explosives are chemicals releasing lot of heat energy to the surrounding upon decomposition. Nitrogen compounds, hydrogen etc are explosive and they will explode in air or water.
Chemicals have to handled carefully and stored as per the conditions based on their chemical and physical properties. Some of them may easily corrode. Some may rapidly reacts with water or air and some may explode in air.
Explosive chemicals causes atmospheric pollution as well as health risk by releasing hazardous chemicals. If they are contaminated then there may occur some unwanted reaction and it will make the risk intense by producing toxic gases.
To find more about explosives, refer here:
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The process by which cells divide is called
A
O replication
B.
mitosis
C.
respiration
D.
photosynthesis
the answer is mitosis
Which branch of chemistry would be used to make steel?
Answer:
the five major branches of chemistry are organic, inorganic, analytical, physical, and biochemistry.
HELP I need these 2 questions answered
Answer:
1=a 2=d i think
Explanation:
what's the pH of a solution composed of 0.2 moles of NH3 and 0.15 moles of nh4cl
Answer:
[tex]pH=4.63[/tex]
Explanation:
Hello!
In this case, since the ionization of ammonia, which is a weak base, is written as:
[tex]NH_3+H_2O\rightleftharpoons NH_4^++OH^-[/tex]
We can see that the ammonium ion is the conjugate acid whereas the hydroxide ions the conjugate base; that is why we use the Henderson-Hasselbach equation to compute the pH, given the pKb of ammonia 4.75:
[tex]pH=pKb+log(\frac{[conj\ acid]}{[base]} )[/tex]
In such a way, for the given moles of ammonia, base, and those of ammonium chloride, conjugate acid form, we obtain:
[tex]pH=4.75+log(\frac{0.15}{0.2} )\\\\pH=4.63[/tex]
Best regards!
How many grams are in 4.7 moles of Na2O?
290 g Na₂O
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Atomic Structure
Reading a Periodic TableUsing Dimensional AnalysisExplanation:Step 1: Define
4.7 mol Na₂O
Step 2: Identify Conversions
Molar Mass of Na - 22.99 g/mol
Molar Mass of O - 16.00 g/mol
Molar Mass of Na₂O - 2(22.99) + 16.00 = 61.98 g/mol
Step 3: Convert
Set up: [tex]\displaystyle 4.7 \ mol \ Na_2O(\frac{61.98 \ g \ Na_2O}{1 \ mol \ Na_2O})[/tex]Multiply: [tex]\displaystyle 291.306 \ g \ Na_2O[/tex]Step 4: Check
Follow sig fig rules and round. We are given 2 sig figs.
291.306 g Na₂O ≈ 290 g Na₂O
Many reactions double their rates with every ten degrees rise in temperature. Assume that such a reaction takes place at 301 K and 311 K. What must its activation energy be for this statement to hold
Answer:
57.6 KJ/mol
Explanation:
We have that;
T1 = 301 K
T2= 311 K
k1 = k1
k2= 2k1
R = 8.314 JK-1
Ea= ?
So;
ln(k1/k2) = (-Ea/R) (1/T1 - 1/T2)
ln (k1/2k1) = -(Ea/8.314) (1/301 - 1/311)
ln(1/2) = -(Ea/8.314) (3.3 * 10^-3 - 3.2 * 10^-3)
-0.693 = -(Ea/8.314) 0.1 * 10^-3
-0.693/ 0.1 * 10^-3 = -(Ea/8.314)
-6930 = -(Ea/8.314)
Ea = 6930 * 8.314
Ea = 57.6 KJ/mol
When a chemical change occurs _____.
Need ASAP please someone
Select one:
a. atoms are rearranged
b. the law of conservation of mass is always obeyed
c. the chemical properties of new substances are different from the ones you started with
d. all of these
Answer:
d
Explanation:
i think its d but im not sure.
What is the mass of 2.53x10^34 atoms of Ni?
Answer:
2.48 g
Explanation:
From the question given above, the following data were obtained:
Number of atoms = 2.53×10³⁴ atoms
Mass of Ni =?
From Avogadro's hypothesis,
we understood that 1 mole of any substance contains 6.02×10²³ atoms.
Therefore, 1 mole of Ni contains 6.02×10²³ atoms.
Recall:
1 mole Ni = 59 g
Therefore, 59 g of Ni contains 6.02×10²³ atoms.
Finally, we shall determine the mass of 2.53×10³⁴ atoms of Ni. This can be obtained as follow:
6.02×10²³ atoms = 59 g
Therefore,
2.53×10³⁴ = 2.53×10³⁴ × 59 / 6.02×10²³
2.53×10³⁴ atoms = 2.48 g
Thus, the mass of 2.53×10³⁴ atoms of Ni is 2.48 g.
which type of organism carries out cellular respiration
Answer:Prokaryotic cells carry out cellular respiration within the cytoplasm and eukaryotic cells carry out respiration in the mitochondria
Explanation:
Touching a hot stove or the melting of ice in your hand (as you squeeze it) is an example of
Answer: conduction
Explanation:
the heat passes out of the stove and into your hand. So is holding an ice cube – the heat is conducted out of your hand, and into the ice cube (that’s why your hand feels cold).
Answer:
Conduction
Explanation:
Conduction occurs when objects touch. The heat from the warmer object is transferred to the cooler object, eventually evening out the temperatures.
at a particulat temperature, a smaple of pure water has a Kw of 7.7x10-14. what is the hydroxide concentration of this sample
Answer: The hydroxide concentration of this sample is [tex]3.85\times 10^{-7}[/tex]
Explanation:
When an expression is formed by taking the product of concentration of ions raised to the power of their stoichiometric coefficients in the solution of a salt is known as ionic product.
The ionic product for water is written as:
[tex]K_w=[H^+]\times [OH^-][/tex]
[tex]7.7\times 10^{-14}=[H^+]\times [OH^-][/tex]
As [tex][H^+]=[OH^-][/tex]
[tex]2[OH^-]=7.7\times 10^{-14}[/tex]
[tex][OH^-]=3.85\times 10^{-7}[/tex]
Thus hydroxide concentration of this sample is [tex]3.85\times 10^{-7}[/tex]
Which of the following is not a natural change to the envlronment? drought , flood, disease ranching
Answer:
Disease ranching
Explanation:
Floods and Droughts are caused by the enviorment. Diseases are but a product and don't affect the enviorment.
Answer:
disease ranching is not a natural change to the environment .
Explanation:
This all happen because of human activities
For all seawater problems, assume the salinity is 3.5%
If you have a 2000 gram sample of seawater, how many grams of pure water are there?
0.035 x 2000) = x, 2000 - x = pure water
Answer to the nearest WHOLE number.
Answer:
1930g
Explanation:
We have been given that the salinity of sea water is 3.5%;
Now the mass of sea water sample is 2000g
So, problem here is to find the quantity of pure water in the sample = ?
Solution:
Let us find the quantity of the salt in the sample;
Salt content = 3.5% x 2000 = 70g
Amount of pure water = 2000 - 70 = 1930g
Why did the French set up trading posts in North America?
Answer: Their main aim was to provide goods, specifically furs and sugar exportation.
Explanation:
how does heat transfer into conduction
Explanation:
Heat is transferred by conduction when adjacent atoms vibrate against one another or electrons move from one atom to another . Conduction is the most significant meanings of heat transfer within a solid or between solid objects informal contact.