Do it for 60 points pleaseee
Answer:
period number
Answer:
Period number
Explanation:
Period number is the answer.
Hope this is right!
which of the following do all living organisms have in common ?
Chloe is training for her first half-marathon, which requires her to run 21.1 km. Before she runs, she carefully chooses the foods that will give her the energy her body requires for the race. She stands still at the starting line, then she starts running, her body warming up as she runs. Which three energy transformations take place in this example? Potential energy to kinetic energy Chemical energy to thermal energy Chemical energy to kinetic energy Mechanical energy to chemical energy
Answer:
The transformation is of chemical energy (use the ATP molecule as a resource) which is then transformed into mechanical energy (muscle contraction) and finally transformed into thermal energy (increase in body temperature, or sweating)
Explanation:
Energy is never lost, it is always transformed, that is why energy is yielding electronic movement and expressing itself in different ways, first as chemical energy, then as mechanical energy, and lastly as thermal energy.
It is important to clarify that the energy source of all this transformation is food and energy reserves.
When your food gets digested, the macromolecules get broken down into
individual monomers. Which monomer would be most present based on your meal?
How do you know?
The atomic masses of elements are generally not whole numbers. Explain why.
Answer:
Because elements have isotopes.
Explanation:
So the atomic mass is the average of an element's isotopes.
Answer:
The atomic masses of most elements are not whole numbers, because they are a weighted average of the mass numbers of the different isotopes of that element, with respect to their abundances in nature.
Explanation:
Sodium electron configuration in longhand notation
Answer:
Na₁₁ = 1s² 2s² 2p⁶ 3s¹
Explanation:
Sodium is present in group 1.
It is alkali metal.
It has one valence electron.
The atomic number of sodium is 11.
Its atomic mass is 23 amu.
The longhand notation of electronic configuration of sodium can be written as,
Na₁₁ = 1s² 2s² 2p⁶ 3s¹
The electronic configuration in shorthand notation( noble gas) would be written as,
Na₁₁ = [Ne] 3s¹
Sodium loses its one valence electron to complete the octet and get stable thus form +1 cation.
It react with halogen and form salt. Such as sodium chloride.
2Na + Cl₂ → 2NaCl
7)
What is the correct name for the compound, P2O5?
A)
diphosphorus pentoxide
B)
phosphorus pentoxide
6)
diphosphorus oxide
D)
phosphorus oxide
Phosphorus pentoxide is a white solid that has no noticeable smell. This substance has the chemical formula P₄O₁₀. But its name comes from its empirical formula, P₂O₅. Here the correct option is B.
This substance is a white solid with a crystalline structure at room temperature. An acid anhydride made from phosphoric acid is phosphorus pentoxide. Due to its strong hygroscopicity, it is employed as a desiccant and a dehydrating agent.
When in contact with water, phosphorus pentoxide hydrolyzes quickly and violently. This reaction produces a lot of heat. The four polymorphs of this chemical that crystallize are different. Because it is so corrosive, metals must be kept away from it.
Thus the correct option is B.
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Air is a mixture of different gases like nitrogen and oxygen. Carbon dioxide is the most important contributor to human-caused global warming. _________________ _________________ Forest fires and cities with lots of car traffic cause air pollution.
Is burning the glass plate is physical or chemical change?
Would love some help pleaseee. and please at least read the question instead of skipping it please.
Measuring tools can have errors. Errors lead to ___________________ results and _______________ conclusions. To calculate the difference of the accepted value and the experimental value, scientists use this formula:
percent error = (experimental value − ) × 100. accepted value
Minimizing Bias
People show bias when they want everyone to accept their results. Bias can arise for many reasons:
• Companies show bias when they depict only the research details that are in the best interest of their ____________.
• Scientists may be biased toward their _____________ and modify results suit their needs.
• Scientists may also show to bias get their research published in ______________ ______________.
Such biases often lead to _______________ facts. An important part of scientific thinking is identifying biases and taking the necessary steps to minimize them.
For results to be considered scientifically accurate, any scientist, regardless of his or her own bias, should be able to replicate the experiment and get the same results.
Summary
Think of some studies you’ve heard about. How can you tell whether the studies were well-designed and scientifically accurate or had biases?
Answer: this looks like your homework
Explanation:if you want help you are going to have to ask a specific question instead of giving people your homework.
Answer:
Honestly I would search this up maybe there might be a pdf with the answers. Sorry chemistry isn't my thing:(
Explanation:
How does pentane and butane differ from each other
Answer:
Butane has only two isomers and pentane has just three, but some hydrocarbons have many more isomers than these. As you increase the number of carbon atoms in a hydrocarbon, the number of isomers quickly increases.
Atoms with a different number of protons than electrons are called:
Answer:
Hello!!! Princess Sakura here ^^
Explanation:
They are called isotopes.
Answer:
A positive ion.
Explanation:
I think
Identify the reaction type shown and describe the clues that were used to identify it.
Fe2O3 + 2SiO2 → Fe2Si2O7
what unit of measure would i use to measure the width of my fingernail A millimeters
B centimeters C meters D kilometers
E grams
What happens in the nucleus when a lithium atom becomes an ion
Answer:
An atom that gains a negative electron, it becomes a negative ion. ... A lithium atom has 3 protons and 3 electrons. It can lose one of its electrons, making it an ion. It now has more positive protons than electrons so it has an overall positive charge.
Answer:
This means a Lithium atom formed into a Lithium ion by losing one of its electrons. It has three electrons and three protons to begin with. So when it loses or gains one the amount isnt equal, that is why it becomes an ion. If it gained electrons it would have a negative charge on the nulcleus, though if it lost electrons it would have a positivec charge. Hope this helped!!
Silver is a white metal that is an excellent conductor. Silver tarnishes when exposed to air and light. The density of silver is 10.49 g/cm3. The melting point is 962oC and the boiling point is 2000oC. A chemical property of silver is A) density. B) melting point. C) tarnishes in air. D) that it is a conductor.
Answer:
c tarnishes in air
Explanation:
After silver has been exposed to air that contains sulphur gases, discoloration would occur. there would be darkening that is caused by the reaction with gases.When any silver object tarnishes, it brings about a disfiguring of that object. Hydrogen sulphide would be needed for this to happen. silver sulphide is black and a if a thin layer should form on any surface, it ill darken it. This is what we refer to as tarnishing.
Answer:
c
Explanation:
it tarnishes in air
Percent occurrence and isotope masses for oxygen: 99.759 % at 15.99491 amu, 0.037% at 16.99913 amu and 0.204% is at what amu value, if the average atomic mass is 15.99937 amu?
Show work
Answer:
15.99937 is the value of this question answer
in the chemical equation HCI+CaCO3 which element cannot be apart of the products a carbon b chlorine c nitrogen d oxygen
Answer:
Nitrogen
Explanation:
The element nitrogen cannot be a product in the given reaction.
The reaction is;
HCl + CaCO₃
According to the law of conservation of matter, "matter is neither created nor destroyed in the cause of a chemical reaction".
The law suggests that, in a chemical reaction, we end up with the same species we started with. Although due to rearrangement of bonds, new compounds can form;
Starting atoms
H
Cl
Ca
O
These species will also be found in the product.
Consider a 5.430 g mixture of FeO and Fe3O4. You react this mixture with excess of oxygen to form 5.779 g Fe2O3. Calculate the percent mass of FeO in the original mixture.
Answer:
Explanation:
A 5.430 g mixture of FeO and Fe3O4 is reacted with excess of oxygen to form 5.779 g Fe2O3. Find the masses of FeO and Fe3O4 present in the mixture.
I found the answer by doing the following:
Fe2O3 = 159.69 g/mol
FeO = 71.745 g/mol
Fe3O4 = 231.535 g/mol
5.779 g Fe2O3 / 159.69 g/mol = 0.03619 mol Fe2O3
x + y :rarrow: 0.03619 mol Fe2O3, where x = FeO and y = Fe3O4.
This implies that y = 0.03619 - x.
5.430 g = x*71.745 g/mol + (0.03619 - x)*231.535g/mol
x = 0.01846 mol * 71.745 g/mol = 1.324 g FeO
y = 0.03619 - 0.01846 = 0.01773 mol * 231.535 g/mol = 4.105 g Fe3O4
My question is why doesn't the following work:
4FeO + O2 :rarrow: 2Fe2O3
4Fe3O4 + O2 :rarrow: 6Fe2O3
_______________________
2FeO + 2Fe3O4 + O2 :rarrow: 4Fe2O3
5.779 g Fe2O3 / 159.69 g/mol = 0.03619 mol Fe2O3
Product:reactants in question are in a 2:1 ratio as given by the stoichiometric coefficients.
0.03619 mol / 2 = 0.01810 mol of FeO and 0.01810 mol Fe3O4.
0.01810 mol FeO * 71.745 g/mol = 1.299 g FeO
0.01810 mol Fe3O4 * 231.535 g/mol = 4.191 g Fe3O4
Obviously this doesn't work because the original mixture is 5.430 g and not 1.299 g + 4.191 g = 5.490 g. Why doesn't this work the way I think it should? Thank you.
Which is a way that the model of the atom became stronger through new experiments? (1 point)
a
New technology allowed scientists to show that the atom is indivisible.
b
It took new data to show that positive charge is not spread throughout an atom.
c
By deflecting alpha particles, Rutherford first observed the neutron.
d
The neutron could not be detected until Cathode–Ray Tubes were invented.
Answer:
Explanation:
Key points
J.J. Thomson's experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons.
Thomson's plum pudding model of the atom had negatively-charged electrons embedded within a positively-charged "soup."
Rutherford's gold foil experiment showed that the atom is mostly empty space with a tiny, dense, positively-charged nucleus.
Based on these results, Rutherford proposed the nuclear model of the atom.
use the Kinetic Theory to explain the following. when you come home from school and open the door you can smell your tea being cooked
Answer:
Tea is getting hot on the stove.
2) As the tea and water gets hot, some combined molecules of tea and water will escape from the teapot.
3) Those escaped molecules now have the entire free space of the entire room to float around in, which they do (because they have high kinetic energy due to being heated).
4) Hence, in this scenario, your nose will detect a few of those molecules and you smell hot or warm tea.
5) Cold tea would be a different story. Cold beverages like cold tea do not have the kinetic energy where molecules can 'break free' of the surrounding container. Someone could be sitting in the room having a can or bottle of cold tea and you would not notice that when you walked in the door.
1. Using a triple beam balance and a graduated cylinder, a student collected data on a sample of an
element:
Mass of sample - 67.9 g
Volume of water - 52.0 ml
Volume of water and sample - 28.0 ml
a) Calculate the density of the sample. Show all work and use significant figures and units.
Answer:
d = 2.8 g/mL
Explanation:
Given data:
Mass of sample = 67.9 g
Volume of water = 28.0 mL
Volume of water + sample = 52.0 mL
Density of sample = ?
Solution;
Density is equal to the mass of substance over volume of substance.
Formula:
d = m/v
d = density
m = mass
v= volume
Now we will calculate the volume of sample.
Volume of sample = (volume of water+ sample) - volume of water
Volume of sample = 52.0 mL - 28.0 mL
Volume of sample = 24.0 mL
Now we will calculate the density.
d =67.9 g /24.0 mL
d = 2.8 g/mL
Why does wood float besides it being less dense
Answer:
The only reason wood floats is because it is less dense and has big openings and gaps which allows air in.
Wood that sinks has very tiny openings. The ratio between weight and volume is called density. An object that is less dense than water can be held up by water, and so it floats.
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Convert 427 Liters of CO2 to moles.
Answer:
9.702450607255294
.....0
0. 10. A black hole is a region in space where the gravational poll is so great that
It can be used to travel to another universe,
0
It consumes entire galaxies.
O
Light cannot escape
New stars are formed,
Answer:
light cannot escape new stars are formed
Explanation:
Pedro is baking a cake for his experiment on chemical changes. He knows a chemical change will occur when he puts the cake mixture in the oven. He would like to know what will happen when the cake is removed from the oven. What prediction would you make for Pedro's experiment? A. The chemical changes occurred because the chemicals changed. B. The chemical changes occurred because there was a change in light energy. C. The fruit and the hamburgers were affected by an increase in heat energy. D.The fruit and the hamburgers were affected by a decrease in heat energy.
Answer:
A. The chemical changes occurred because the chemicals changed.
Explanation:
When baking a cake several chemical reactions occur that change the chemical composition of the ingredients used in baking. An ingredient like baking powder releases carbon dioxide when it undergoes a temperature change in the oven. A chemical change is supposed to change the form of a substance.
An endothermic reaction also occurs when the ingredients absorb heat energy to produce several changes. The firmness of the cake occurs because of the heat absorbed by the proteinous content of the egg.
Which of these statements describes a chemical property?
Answer:
it rusts when exposed to air
Answer:
A
Explanation:
What is the mass in grams of o.0135
mol of the element sodium, Na?
Answer:
0.311g
Explanation:
n= m
M
where n is moles
m is mass of substance
M is molar mass
Mn = m
0.0135×23=m
0.311=m
Which answer choice best explains why nuclear reactions release more energy than chemical reactions? Electrostatic forces of repulsion are thousands of times stronger than gravitational forces. Gravitational forces are thousands of times stronger than electrostatic forces of repulsion. The force that binds together protons and neutrons is stronger than the force that attracts and repels protons and electrons. The force that attracts and repels protons and electrons is stronger than the force that binds together protons and neutrons.
Answer:
The force that binds together protons and neutrons is stronger than the force that attracts and repels protons and electrons.
Explanation:
1. Protons are positively charged. Protons have a mass of 1.
2. Neutrons are uncharged. Neutrons have a mass of 1.
3. Electrons are negatively charged. Electrons have almost no mass.
Nuclear reactions release more energy than chemical reactions as the force that binds together protons and neutrons is stronger than the force that attracts and repels protons and electrons.
Answer:
C) The force that binds together protons and neutrons is stronger than the force that attracts and repels protons and electrons.
Explanation:
list in the following elements in order of smallest to largest atomic radius. F, Cl, Br, l
And which has a larger atomic radius?