Answer:
she bought 3 erasers an got two dollars back
Explanation:
A length of wood has a labeled length value of 2.50 meters. You measure its length three times. Each time you get the same value: 2.35 meters. What is the percent error of your measurements? *
Answer:
6%
Explanation:
Actual length of the wood is 2.5 m
Observed length of the wood is 2.35 m
We need to find the percent error of your measurements. The formula of the percentage error is given by :
[tex]\%=\dfrac{|\text{observed-actual}|}{\text{actual}}\times 100\\\\\%=\dfrac{2.5-2.35}{2.5}\times 100\\\\\%=6\%[/tex]
Hence, the percentage error is 6%.
rabbit is one of the sweetest animal on world ....change it into positive degree
Answer:
rabbit is one of the sweet animal
in the world
A student says: Potassium (K) always has 20 protons. Explain why the student is incorrect.
Explanation:
19
Potassium/Atomic number
This tells you that potassium has 19 protons and - since the number of protons is the same as the number of electrons- also 19 electrons. To find out the number of neutrons you have to look at the atomic mass or weight of the element. This can also be found in the periodic table.
Is this statement true or false? Why?
Chemical reactions are nothing more than rearrangements of protons.
Answer:
False. Answer in pic above
In fact protons have no role in chemical reactions. The regrouping of atoms itself forms the new products in chemical reactions. The reactions involves the loss/gain or sharing of electrons.
What is a chemical reaction ?A chemical reaction is a chemical change in which two or more atoms combine together to form a new product or a compound decomposes to form its constituent compounds. This involves breaking or making of bonds.
In a chemical reaction, no change occurs in the nuclear composition but the valence electrons are involved in the reaction. Atoms loss or gain electrons or share valence electrons with other atoms to form ne compounds.
The electrostatic force of attraction or the overlapping of atomic orbitals make the new products in a chemical reaction. Hence, the statement is false.
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A cylinder with 10 mL of coconut oil has a mass of 9.3 g. What is the density of the oil? Round to the nearest hundredth.
Answer:
0.93 grams per milliliter
Explanation:
Density is the division of mass by volume. It is how "hefty" an object is; for example, wood isn't very "hefty" but metal is. The density is measured in mass over volume, so it is 9.3/10. After applying units, it is 0.93 grams per milliliter.
If one end of an iron bar is heated, what causes thermal energy to transfer to the other end? a radiation b conduction c heat of fusion d convection
Answer:
Option B:
Conduction
Explanation:
Conduction is the transfer of heat from one molecule to another between two solids that are in direct contact with each other. For the conduction of heat to occur, the medium involved must be solid. This is because the molecules of solids are closely packed together and they cannot freely move about. The heat flowing through them can easily be passed on from one molecule to the other until it reaches all the parts of the object. This is exactly what will happen to the iron bar. Thermal energy from one end of the bar will get transferred between the molecules of the iron bar until it reaches the other end.
Convection on the other hand involves the transfer of heat through a liquid medium.
Radiation involves teh transfer of heat in a vacuum.
Answer:
b) conduction
Explanation:
Define and give 3 examples of psychical properties
Answer:
A physical property is any property that is measurable, whose value describes a state of a physical system.
Explanation:
-color
-density
-volume
is nonflammable a physical or chemical property
6.Think about where you live now or where you have lived in the past; use complete sentences to describe this environment and the weather. What building materials do you believe would work well to build a home in that area? Explain why you chose these materials.
Answer and Explanation:
I have always lived in the same region. The region where I live is flat and stable, the site has asphalt and the climate is tropical with a long summer and poorly defined seasons. My region does not have drastic changes and temperature and the climate is hot most of the year. For this reason, it is necessary to use materials that are thermal insulators, on the contrary we need to use materials that are not good thermal insulators such as concrete blocks, bricks, cement and ceramics, we will also need common tiles and rafters to support them.
The table shows four samples of carbon dioxide and the temperature of the water that they were dissolved in. Which of the samples most likely had the lowest solubility? I know the answer is sample one (78) but i can't find the right words to explain my answer.
Answer:
Sample 1 = 78°
Explanation:
As per the question, while testing the solubility of a solution comprising of water and carbon dioxide, sample 1 is likely to have the lowest solubility with the temperature of the water being 78°, the maximum. The reason for this result is that the 'solubility of carbon dioxide in the water' falls with an increase in the temperature due to the increase in kinetic energy which will enhance the motion between the molecules and allow them to escape.' Thus, the water with maximum temperature will have the lowest solubility. Hence, sample 1 is the correct answer.
What are the units for Rf values? Please help!
Answer:
Microwatts.
Explanation:
RF + EMF Unit Conversion Charts: Interpreting exposure levels. When measuring Radio Frequencies, the most common units of measurement are microwatts per square meter (µW/m2), microwatts per square centimeter (µW/cm2) and volts per meter (V/m).
Answer:
No units
Explanation:
In Thin Layer Chromatography (TLC), retention factor (Rf value) is found by taking the distance travelled by the spot divided by the distance of the solvent front. Rf value is a ratio of distances hence they have no units.
Mathematical derivation
The distance travelled by the spot is in cm, and that of the solvent front is also in cm. Thus, dividing the two units would give us no units for the Rf value.
What is TLC?
TLC is a technique used for separation and identification. The stationary phase is polar while the solvent is relatively nonpolar. Thus, the less polar substance is more attracted to the solvent (according to the principle of 'like attracts like') and travels further and thus have a higher Rf value.
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Convert 35 mL to cm3. 1 mL = 1 cm3
how to calculate molecular mass?
Which of these elements have just one valence electron?
Answer:
Only Hydrogen and Group 1 elements have 1 valence electron
Explanation:
the valence number of electrons is the group number in the periodic table. So, the group 1 atoms( along with hydrogen) have 1 outer-shell electrons [valence electrons]
How many moles ar Li are in 9.53x^24 atoms of Li?
Answer: 15.83 mol
Explanation:
To convert from atoms to moles, we will need to use Avogadro's number.
Avogardo's number: 6.022×10²³ atoms/mol
[tex]9.53*10^{24} atoms*\frac{1mol}{6.022*10^2^3 atoms} =15.83 mol[/tex]
Now, we know that there are 15.83 moles.
Which of the following happens during a chemical reaction?
Atoms of reactants are destroyed.
New atoms are created to form the products.
Atoms of reactants rearrange to form new substances.
The total mass of the reactants is less than the total mass of the products.
Answer:
Atoms of reactants rearrange to form new substances
Explanation:
During a chemical reaction, atoms of reactants rearrange to form new substances.
What is a chemical reaction?Chemical reactions are defined as reactions which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical reaction.
There are several characteristics of chemical reactions like change in color, change in state , change in odor and change in composition . During chemical reaction there is also formation of precipitate an insoluble mass of substance or even evolution of gases.
There are three types of chemical reactions:
1) inorganic reactions
2)organic reactions
3) biochemical reactions
During chemical reactions atoms are rearranged and changes are accompanied by an energy change as new substances are formed.
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What is the force of gravity acting on an object? (3 points)
Velocity
Mass
Weight
Pounds
the answer of these question is weight
Express a mass of 0.056 mg in grams.
Answer in units of g.
Answer:
0.000056g
Explanation:
1 mg = 0.001 g
Or if it helps move your decimal sign over left 3 places.
3
Write the alpha decay WITH gamma emission for the following element:
92
AL
27
Answer:
Explanation:
In alpha decay alpha ray comes out . Apha ray is nothing but nucleus of helium atom whose atomic no is 2 and atomic weight is 4 . Hence in alpha decay , atomic weight reduces by 4 and atomic no reduces by 2. For gamma emission , there is no change in atomic number and atomic mass.
⁹²₂₇AL ⇒ ⁸⁸₂₅X + ⁴₂He + γ
X is Manganese .
The head of a pin is 1.5 × 10-3 m in diameter. If 1.136 × 107 atoms of oxygen can fit across the head of a pin, what is the atomic radius of oxygen?
About five million million hydrogen atoms could fit. Some factors would affect that number like the area of the head and the size of atoms (as well as attractions between atoms). Some atoms are larger than others.
If 1.136 × 10⁷ atoms of oxygen can fit across the head of a pin whose diameter is 1.5 × 10⁻³ m, the atomic radius of oxygen would be 6.60 × 10⁻¹¹ m.
The head of a pin is 1.5 × 10⁻³ m in diameter. If 1.136 × 10⁷ atoms of oxygen can fit across the head of a pin, the diameter of each oxygen atom would be:
[tex]\frac{1.5 \times 10^{-3}m }{1.136 \times 10^{7}atom} = 1.32 \times 10^{-10}m/atom[/tex]
The atomic radius of oxygen would be half of its diameter.
[tex]\frac{1.32 \times 10^{-10} m}{2} = 6.60 \times 10^{-11} m[/tex]
If 1.136 × 10⁷ atoms of oxygen can fit across the head of a pin whose diameter is 1.5 × 10⁻³ m, the atomic radius of oxygen would be 6.60 × 10⁻¹¹ m.
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Give 5 examples of branches of science, then give an example of situations that apply the use of it in daily activities. Example: PHYSICS - Turning the light on and off.
Answer:
See explanation
Explanation:
Biology- digestion of food materials
Chemistry- dissolving salt in water
Astronomy - observing day and night
Physics - watching a television
Geography - observing weather changes during the day
what number and types of atoms occur in a formula unit of CaN2O6
Answer:
One calcium, two nitrogen, and six oxygen
Explanation:
1. How many molecules are in 2.40 moles of H2O?
Answer:
There arr 1.5*1024 molecules in 2.40 moles of H2O.
PSYCHOLOGY All of the following physical reactions occur when our fight-or-flight response is triggered except __________. A. dilating pupils B. increasing heartbeat C. increasing digestion D. increasing perspiration
Answer:
C.) increasing digestion
Explanation:
hope this helps:)
Answer:
C. increasing digestion
Explanation:
Which statement accurately describes the chemical symbol of an element?
O The chemical symbol is always a single letter.
O The chemical symbol always starts with the same letter as the name of the element.
O The chemical symbol always begins with a capital letter.
OThe chemical symbol can be shared by more than one element.
Answer:
The chemical symbol always begins with a capital letter.
Explanation:
Answer:
c
Explanation:
The chemical symbol of an element always starts with an chemical letter so here the answer is that the chemical symbol always begins with a capital letter.
It can be seen in the different elements chemical symbol .
For example, Tin is having chemical symbol as Sn while lead is having chemical symbol as Pb.
In both these elements, the chemical symbol starts with a capital letter but none of these have their symbol starts with same letter as their name.
How many electrons does the Ca^2+ ion possess
Answer:
18 electrons
Explanation:
Answer:
18 electrons
Explanation:
Ca has 20 electrons. Ca^2+ has 18 electrons
how does kinetic energy at the bottom of a hill compared to its potential energy at the top
Answer:
Kinetic energy would have to work ten times harder than potential energy.
Explanation:
Let’s say you have a boulder and your asked to push it up the hill it would be difficult right? But lets reverse the situation what if you are asked to roll the boulder down the hill it wouldn’t be much work because the hill is basically doing all the work For you. Hope this Helps:)
What happens when aluminum fills its valence shell? A. Three electrons are gained, creating Al−3. B. Three electrons are gained, creating Al+3. C. Three electrons are lost, creating Al−3. D. Three electrons are lost, creating Al+3.
Answer:
B
Explanation:
Answer:
its D I just took the test
Explanation:
Please help me with this question.
Answer:
12?
Explanation:
Answer:
8
Explanation:
haploid is half
Mass = 35g Volume = 7cm³ What is the Density?
Answer:
The answer is
5.0 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question
mass = 35 g
volume = 7 cm³
The density is
[tex]density = \frac{35}{7} \\ [/tex]
We have the final answer as
5.0 g/cm³Hope this helps you