Answer:
pure substance does not contain two or more elements
Describe the S-wave shadow effect of earth quakes.
Answer: The shadow zone is the area of the earth from angular distances of 104 to 140 degrees from a given earthquake that does not receive any direct P waves. The shadow zone results from S waves being stopped entirely by the liquid core and P waves being bent (refracted) by the liquid core.
Explanation: 104 to 140 degrees from a given earthquake
What is an active metal?
A. a metal that reacts with oxygen
B. a metal that is above hydrogen in the activity series
C. a transition metal
D. a metal with only one valence electron
Answer:
A metal is said to be an active metal when it reacts strongly and quickly with other elements due to the electrons in its structure and its ease of sharing the electrons with other elements. ... A metal's reactivity increases as we go from the top to the bottom of the periodic table.
Explanation:
if you can’t already tell by the amount of questions i do not understand chemistry lol, giving brainliest
Answer:
Ok, so the process here is to convert the mass of H2 (hydrogen gas) to moles by dividing the mass by the molar mass of H2. Once you have the moles then you have to multiply by the STP (standard temperature and pressure) molar volume which should be 22.4.
Molar mass of H2 = (1.01)x2 = 2.02g/mol
19.3/2.02 = 9.55 moles
Now just multiply the moles by the molar volume
9.55 moles x 22.4 = 213.92 Litres of H2 are in 19.3g of H2
Tell me What is an element?
Answer:
Any substance that cannot be decomposed into simpler substances by ordinary chemical processes.
Another definition:
An element is the simplest pure substance which can neither be split nor built up from other simpler substances by chemical reaction
50 POINTS PLEASE HELPP
Circle the compound that has the higher boiling point and explain why we see the
differences we do
Answer:
1. Ethane has a higher boiling point
2. Heptyne has a higher boiling point
3. Octane has a higher boiling point
Explanation:
1. Ethane has stronger intermolecular attractions (van der Waal's forces) than ethene and so has the higher boiling point.
2. The longer (and the straighter) the chain, the greater the opportunity for intermolecular interactions, and thus the greater the boiling point. You should look up these boilig points! n-Pentane has a normal boiling point of approx. 36 ∘C ; n-heptane boils at 98 ∘C .
3. Octane has a high boiling point, because its molecule contains 8 Carbon atoms, and with increasing molecular weight of hydrocarbon its boiling temperature increases.
Iron reacts with oxygen and water to create rust and hydrogen gas as shown in the chemical equation. What mass of rust, to the nearest hundredth gram, is produced in this reaction?
A) 4.3 g
B) 5.8 g
C) 16.8 g
D) 29.4 g
Answer:
i think its 5.8
Explanation:
state one cause of temporary hardness of water
Answer:
Temporary hardness of water is caused when thermally unstable chemicals like magnesium hydrogen carbonate and calcium hydrogen carbonate are dissolved in water. Temporary hardness is treated by heating the hard water.
Hope that helps. x
Identify the total number of molecules in the chemical formula: 6CH4 a 6 b 10 c 24 d 30
Answer: A.6
Explanation:
The total number of molecules in the chemical formula is 6
What is a molecule?
Molecules are the smallest particle of a substance that has all of the physical and chemical properties of that substance. Molecules are made up of one or more atoms.
The correct form of question will be:-6 molecule of methane CH₄
6CH4
a) 6 c) 10 c) 24 d) 30⇒ Number of aton of carbon is 6
⇒Number of atom of hydrogen is 24
⇒Total number of atom is 30
What is an atom ?
An atom is a particle of matter that neither be created nor be destroyed. An atom consists of a central nucleus that is usually surrounded by one or more electrons. Each electron is negatively charged. The nucleus is positively charged, and contains one or more relatively heavy particles known as protons and neutrons.
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answer this bs for me pls
Answer:
B.chlorine ,Cl2 is the one
An endothermic reaction occurs when water and ammonium nitrate are combined. Which of the following statements correctly
describes the energy changes in the reaction?
OA. Energy is released because the reactants have more chemical energy than the products.
OB. Energy is absorbed because the reactants have more chemical energy than the products,
OC. Energy is absorbed because the products have more chemical energy than the reactants.
OD. Energy is released because the products have more chemical energy than the reactants.
Answer:
C.Energy is absorbed because the products have more chemical energy than the reactants.
Explanation:
Is a change in color when combining two substances normally a sign of a chemical change or a physical change?
Answer:
Change in colour is a chemical change.
Explanation:
Because when two substances combine chemically, they create (a) new substance(s) that have/has different molecular structures from the parent substances, thus mostly likely absorb and reflect light in different ways.
which type of bonding is found in all substances made up of molecules?
Answer:
Chemical bonds
Explanation:
Chemical bonds are forces that hold atoms together to make compounds or molecules. Chemical bonds include covalent, polar covalent, and ionic bonds. Atoms with relatively similar electronegativities share electrons between them and are connected by covalent bonds.
The main-group elements are the forty-four elements that occupy groups 1A-8A of the periodic table. Main-group elements are important because of their high natural abundance both in the Earth's crust and in the human body and are commercially valuable. Review the families containing main group elements. Identify all the characteristics that apply to the elements in family IA.
Answer:
The answer is a,b, and c. This is for the USA tesprep videos
Explanation:
The characteristics that apply to the elements in the family are they are highly reactive, they are shiny, soft metals and the element form +1 ions when forming compounds. Thus option a, b and c is correct.
What are main group elements?Main group elements are defined as any of the element belonging to the s and p blocks of the periodic table.
They are most abundant element in universe and on earth.
This elements and their compound are one of the most important economical elements.
They are very good conductor of heat and electricity.
Thus, the characteristics that apply to the elements in the family are they are highly reactive, they are shiny, soft metals and the element form +1 ions when forming compounds. Thus option a, b and c is correct.
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Do cells have atoms?
Answer:
Ye? everything is made up of atoms so sure
Leslie is a forensic scientist who is using the precipitin test at a crime scene. What
question is Leslie MOST likely trying to answer?
Answer:
How long has this blood been here?
Explanation:
Answer:
Leslie is a forensic scientist who is using the precipitin test at a crime scene. What question is Leslie MOST likely trying to answer?
Explanation:
Leslie is a forensic scientist who is using the precipitin test at a crime scene. What question is Leslie MOST likely trying to answer? got the answer from quilt
Like the success of animals, the success of plants is limited based on the resources available to each individual. In the tropical
rainforest, plants are especially limited by the spate they have available to grow and reproduce. Which of these statements
describes a way that limited space will impact
the success of a plant in the rainforest? (SC.7.L.17.3)
A plant without enough space will face increased predation from herbivores
a
O A plant without enough space will not have as many parasites and diseases.
3
A plant without enough space will be more likely to be impacted by air quality
A plant without enough space will not be able to capture enough light to grow.
A plant without enough space to grow may be impacted by inadequate air as well as light for proper growth.
The competition for space in the tropical rainforest has impacts on two processes:
Light for photosynthesisAir for growthLight is very important for photosynthesis and the overall well-being of plants. In a tight space, light and air become limited. This means that plants growing in such a space will not be able to photosynthesize optimally.
Plant roots need air to function properly and when becomes inadequate, the entire plant becomes negatively impacted.
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Select the three hypotheses that explain why being born in the United States leads to a higher chance of developing allergies
- The weather patterns in the United States bring more allergens compared to other countries
- cultural practices may play a part because some cultural foods have different anti-allergenic properties
- other factors which might influence why there are more children with allergies in the United States include climate, obesity, and the typical western diet with high amounts of processed foods.
- children in the United States are taught to believe in allergens, but really allergens don’t really exist.
- The hygiene hypothesis claims that children in the United States are not exposed to enough germs in their infancy and childhood to develop their immune system‘s properly.
The three hypotheses that explain why being born in the United States
leads to a higher chance of developing allergies include the following:
The weather patterns in the United States bring more allergens compared to other countries.Other factors which might influence why there are more children with allergies in the United States include climate, obesity, and the typical western diet with high amounts of processed foods.The hygiene hypothesis claims that children in the United States are not exposed to enough germs in their infancy and childhood to develop their immune system‘s properly.Allergies are caused by a host of factors such as :
ClimateDietImmune systemThese factors is the reason why the chosen hypotheses are the most
appropriate.
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In a bond between potassium (K) and bromine (Br),
A.
the potassium atom will gain an electron and become smaller as a cation, while the barium atom will lose an electron and become bigger as an anion.
B.
the potassium atom will lose an electron and become smaller as an anion, while the barium atom will gain an electron and become bigger as a cation.
C. the potassium atom will gain an electron and become smaller as an anion, while the barium atom will lose an electron and become bigger as a cation.
D.
the potassium atom will lose an electron and become smaller as a cation, while the barium atom will gain an electron and become bigger as an anion.
Answer:
D (But as a heads up, you wrote barium instead of Bromine)
Explanation:
The Potassium atom will lose an electron since its valence shell only has one, while Bromine has 7 electrons in its valence shell. Potassium wants to get rid of its one electron, Bromine wants to gain that one electron to get a full shell.
Potassium will become a CATION with a positive charge (since it lost an electron), Bromine will become an ANION with a negative charge (since it gained an electron)
which of the following substances is most soluble in water
a). table salt
b). baking soda
c). Epsom salt
d). table sugar
Answer:
Table salt
Explanation:
Is most soluble in water
How many atoms of carbon are present in 4.10 moles??!
Answer:
2.4×1024 atoms.
Explanation:
Please mark me as brainliest
9. Any body of rock or sediment in which
water can flow and be stored is called a(n)
a. well.
b. aquifer.
c. sinkhole.
d. artesian formation.
Answer:
It's option b) Aquifer.
What is the mass of air in room
Answer:
the mass of the air in the room is 4.96512 kg ( in 0°C)
1. One atom contains 29 protons and 34 neutrons. Another atom of the same element has a mass number of 65. How many protons and neutrons does this unknown atom have?
A. 28 protons, 37 neutrons
b. 29 protons, 36 neutrons
C. 29 protons, 35 neutrons
D. 31 protons, 34 neutrons
Answer:
b
Explanation:
because its the atom of the same element, the no of protons doesn't change but the mass number changes so we can find the mass number by:
(mass number = atomic no/no of protons + no of neutrons)
here;
mass number given = 65
and we know, no of protons = 29
let no of neutrons = x
hence,
65 = 29 + x
x= 65 – 29
x= 36
hence your answer is b
225 million km to seconds
Answer:
You can't convert km to seconds because they are different units.
Multiply or divide to find the equivalent fraction.
51/120=□/360
Answer
153
Explanation:
51/120 = x/360
51(360) = 120x
18360 = 120x
18360/120x = 120x/120x
153 = x
Answer:
153
Explanation:
Why weren’t scientists initially concerned that the ocean absorbs excess carbon dioxide?
Why scientists weren’t initially concerned that the ocean absorbs excess carbon dioxide was because they saw carbon dioxide as a pollutant
What is a pollutant?Generally, A pollutant is a material found in amounts that are harmful to organisms or exceed an environmental quality standard.
In conclusion, scientists saw carbon dioxide as a major air pollutant, and the water was helping by absorbing it.
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A 12.17 g sample of a compound contains 7.77 g of iron, Fe, 1.44 g of phosphorus, P, and oxygen, O. Calculate the empirical formula for the compound.
Answer:
Fe₃PO₄
Explanation:
They have given the total mass of the compound, the mass of iron and the mass of phosphorus. So we can find the mass of oxygen.
Mass of oxygen = 12.17 - (7.77 + 1.44) = 2.96g
So we can now find the empirical formula.
Element - mass - Mr - Mass÷Mr - Ratio - Simplest Ratio
Fe - 7.77g - 55.8 - [7.77÷55.8] - [0.14÷0.05] - 2.8 = 3
P - 1.44g - 31 - [1.44÷31] - [0.05÷0.05] - 1
O - 2.96g - 16 - [2.96÷16] - [0.19÷0.05] - 3.8 = 4
[The simplest ratio was obtained by dividing the answer of mass÷mr with the smallest value. Phosphorus had the smallest value of mass÷mr=0.05, so all other answer were divided by 0.05]
Emperical formula = Fe₃PO₄
Using the periodic table, choose the more reactive nonmetal.
Br or As
Br and As:
Bromine is more reactive as reactivity increases on moving from left to right in p-block
Solve the following problems and show the complete solutions.
1. How many moles of Carbon Dioxide is equivalent to 1.5X1023 atoms of CO2?
2. If you have 5grams of pure Aluminum, (Al), how many atoms does it have? (Al=27)\.
3. If 3 moles Sodium (Na) reacts with exact Chlorine gas (Cl2) in this reaction: 2Na + Cl2 ---> 2NaCl How many mole of Sodium Chloride (NaCl) will be produced?
4. Give the mass percent composition of Potassium, Sulfur and Oxygen in a molecule of Potassium Sulfate: K2SO4.(atomic mass: K=39, S=32).
5. If 162g of Aluminum reacts with 144g of Oxygen gas to form Aluminum oxide, what is the mass percentage of Aluminum?
6. A sample was analyzed and found to contain 40% Carbon. 6.71% Hydrogen and 53.29% Oxygen. If the molecular mass of this compound is 18.16g/mol, what is the empirical and molecular formula of this compound?
The molecular formula of the compound is C6H12O6.
1) We know that;
1 mole of CO2 contains 6.02 X 10^23 atoms
x moles of CO2 contains 1.5 X 10^23 atoms
x = 1 mole X 1.5 X 10^23 atoms /6.02 X 10^23 atoms
x = 0.25 moles of CO2
2) 1 mole of pure Al has 27 g
x moles of Al has 5 g
x = 1 mole × 5 g/ 27 g
x = 0.19 moles
If 1 mole of Al contains 6.02 X 10^23 atoms
0.19 moles of Al contains 0.19 moles × 6.02 X 10^23 atoms /1 mole
= 1.14 X 10^23 atoms
3) From 2Na + Cl2 ---> 2NaCl;
2 moles of Na produces 2 moles of NaCl hence 3 moles of Na will also produce 3 moles of NaCl.
4) The molar mass of K2SO4 is obtained from;
2(39) + 32 + 4(16) = 78 + 32 + 64 = 174 g/mol
Now;
Percentage by mass of K = 2(39)/ 174 × 100/1 = 44.8%
Percentage by mass of S = 32/174 × 100/1 = 18.4%
Percentage by mass of O = 4(16)/174 × 100/1 = 36.8%
5) The reaction equation is;
4Al(s) + 3O2(g) ----> 2Al2O3
Total mass present = 162g + 144g = 306 g
Mass percent of Al = 162g/ 306 g × 100/1 =52.9%
6)
C - 40/12 H - 6.71/1 O - 53.29/16
C - 3.33 H - 6.71 O - 3.33
Dividing through by the lowest ratio
C- 3.33/3.33 H - 6.71/3.33 O - 3.33/3.33
C - 1 H - 2 O - 1
The empirical formula is CH2O
Now;
[12 + 2(1) + 16] n = 180.16
30n = 180.16
n = 180.16/30
n = 6
The molecular formula is C6H12O6.
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Why are earthworms called as “friends of farmers”? Answer in no less than 4 sentences
Answer:
Organic matter composted with earthworms, often known as vermicompost, has been demonstrated in studies to have disease-suppressing qualities. The earthworms loosen the soil and enrich it with humus. As a result, they are known as farmer's pals. They help the crops grow healthier and over the time have earned farmers trust.
Explanation:
Hope this helps in some way!