40 points.
9. Key Concept How do measurements relate to
experimental science?
10. Key Concept How are accuracy and precision
evaluated?
11. Key Concept Why must a given measurement
always be reported to the correct number of significant figures?
12. Key Concept How does the precision of a calculated answer compare to the precision of the
measurements used to obtain it?
13. A technician experimentally determined the
boiling point of octane to be 124.1°C. The actual
boiling point of octane is 125.7°C. Calculate the
error and the percent error.
14. Determine the number of significant figures in
each of the following.
a. 11 soccer players
b. 0.070 020 meter
c. 10,800 meters
d. 5.00 cubic meters
15. Solve the following and express each answer in
scientific notation and to the correct number of
significant figures.
a. (5.3 104) (1.3 104)
b. (7.2 104) (1.8 103)
c. 104 103 106
d. (9.12 101) (4.7 102)
e. (5.4 104) (3.5 109)
9. Making correct measurements is fundamental to the experimental sciences.
10. Accuracy is the measured value compared
to the correct values. Precision is comparing more than one measurement.
11. The significant figures in a calculated
answer often depend on the number of
significant figures of the measurements
used in the calculation.
12. A calculated answer cannot be more precise than the least precise measurement
used in the calculation.
13. error = –1.6°C; percent error = 1.3%
14. a. unlimited
b. 5
c. 3
d. 3
15. a. 6.6 × 104
b. 4.0 × 10–7 c. 107
d. 8.65 × 10–1
e. 1.9 × 1014
Answer: number 9 is: Measurements are fundamental to experimental science. Number 10 is: To evaluate the accuracy of a measurement, the measured value must be compared to the correct value. To evaluate the precision of a measurement, you must compare the values of two or more repeated measurements. Number 11 is: Measurements must always be reported to the correct number of significant figures because calculated answers often depend on the number of significant figures in the values used in the calculation. Number 12 is: Usually a calculated answer cannot be more precise than the least precise measurement from which it was calculated. Number 13 is: 125.7−124.1=1.6 125.7 − 124.1 = 1.6 degrees Celsius. Number 14 is: a. 11 soccer players- 2 SF b. 0.070 020 meter- 5 SF c. 10,800 meters- 5 SF
d. 5.00 cubic meters- 1 SF.
Number 15 is: A)
Number of significant figures = 2
B)
Number of significant figures = 2
C).
Number of significant figures = 1
D).
Number of significant figures = 3
E).
Number of significant figures = 3
Explanation:
a collective term for several mechanical weathering processes induced by stresses created by the freezing of water into ice. is what? (its ice something) idk the other word:(
Answer: Frost weathering is a collective term for several mechanical weathering processes induced by stresses created by the freezing of water into ice.
The density of liquid Z is 0.9327 g/mL. A student masses a cup with a sample of liquid Z in it and finds the mass to be 50.7 g. The mass of the cup alone is 15.92 g. What is the volume of liquid Z in the cup? (Volume = mass/density)
Answer:
Try doing this: 50.7/.9327 for the answer.
Which of the following is considered a compound?
1) N2
2) Na
3) BF3
select a paragraph that best explain several ways to identify a chemical change through observiation alone?
A. a chemical change occurs when the composition of a substance is changed. chemical change requires the breaking of forming of chemical bonds during a chemical change. The result in arranging of atoms in substances to form the product of the chemical reaction which becomes brand new molecules. These new molecules cannot be easily research it back to their original state
B. sometimes it is difficult to tell if a chemical reaction has taken place. To help determine whether there has been a reaction, chemists consider a few basic indicators. These include a change in temperature, a change in color or the development of an odor.the formation of a participate or the formation of a gas may also indicate a chemical reaction
C. in a chemical alteration a temperature change occurs as a result of a breaking or formation of a chemical bond. When the chemical bonds of the reactants are broken sometimes excesses energy is released. These can cause he choose to be discharged leading to an increase in temperature . burning wood is an example of a reaction that releases at Energy as heat. A chemical cold pack in a first-aid kit in is an example of chemical reaction that absorbs heat energy rather than releasing it.this result in Cooling.
D. a chemical reaction may also release a gas for example a mix of a vinegar and baking soda will immediately start bubbling and foaming.the bubbles are a release of carbon dioxide gas a product of a chemical reaction between these two households substances
Answer:
ITS A OR B
Explanation:
How many phosphorus atoms are in two moles of the compound Mg3(PO4)2? O 4 atoms O 1.2 x 1023 O 2 atoms O 2.4 x 1023
The number of phosphorus atoms : 2.408 x 10²⁴
Further explanationThe mole is the number of particles(molecules, atoms, ions) contained in a substance
1 mol = 6.02.10²³ particles
Can be formulated
N=n x No
N = number of particles
n = mol
No = Avogadro's = 6.02.10²³
moles of Mg₃(PO₄)₂ = 2
moles of phosphorous(P) atoms in Mg₃(PO₄)₂ ⇒ mol ratio of elements in the compound(for P=2)
[tex]\tt 2\times 2=4[/tex]
The number of atoms of phosphorous(P) :
[tex]\tt 4\times 6.02\times 10^{23}=2.408\times 10^{24}[/tex]
Can you help give examples of elements, compounds, and mixtures? My friend is having trouble with it.
Answer:
Elements are all the subtances on the periodic table. Compound are elements that are fused by chemical means like potassium chloride. Mixture are elements that are not chemically fused but just in a sense mixed together.
is it true that Einstein's equation E=mc2 states that matter can be converted to energy. This is an exception to the Law of Conservation of Mass.
The famous formula E=mc^2 really says that mass and energy are the same thing, but measured in different units. So the separate laws of conservation- one for mass and the other for energy- are now merged into one law.
Einstein's theory of special relativity (1905) shows that matter (as mass) and energy can be converted into each other according to the famous equation E = mc2, where E is energy, m is mass, and c is the speed of light.
Hope It helps you.
the first plants to grow after a fire are called?
Answer:
Ephemerals
Explanation:
The first plants to move into the new bare ground after a wildfire are wildflowers or “weeds.” These fast-germinating, leafy herbaceous plants are also known as “forbs” or “ephemerals.” They quickly germinate, grow and produce a new crop of seeds.
Answer:
ephemeral
Explanation:
What general trend do you observe in the periodic table of the Atomic Radius?
Answer:
Atomic radius Increases in groups from top to bottom and decrease in period from left to right.
Explanation:
Which of the following is an example of a covalent compound?
Answer:
CCI2
Explanation:
Why is oxygen heavier than air?
Answer:
Oxygen is denser
Explanation:
Oxygen is denser than both air and nitrogen, at all temperatures and pressures, but only slightly. Since they don't separate from each other, we generally don't worry which is lighter or heavier. The difference in the density of nitrogen and oxygen gas comes from their molecular weight, which is small (4 g/mol)
Answer:
Oxygen is denser than air.
Explanation:
This is because oxygen gas comes from its molecular weight. Also air is mainly made up of nitrogen and nitrogen is lighter than oxygen.
WORTH 20 POINTS PLZZZ HELP WILL GIVE BRANLIEST PLZZZ
A toaster transforms P energy into Q energy.
What do P and Q most likely represent?
P represents electrical energy, Q represents thermal energy
P represents thermal energy, Q represents electrical energy
P represents chemical energy, Q represents radiant energy
P represents radiant energy, Q represents chemical energy
Answer: P represents electrical energy, Q represents thermal energy.
Explanation: The toaster takes electrical energy from the electrical socket through wires and converts that into thermal energy that heats up/toasts the bread.
Answer:
P represents electrical energy, Q represents thermal energy
Explanation:
I am sorry if I get this wrong, but when I put it in the sentence - A toaster transforms electrical energy into thermal energy - it made sense to me, so I think that is the answer. I am sorry if this does not help.
You shoot a beam of 4.5 eV light at a metal surface and notice that electrons are being
released from the metal. What will happen if you then increase the intensity of the 4.5
eV light?
O The metal will bend and warp.
O Nothing, the energy of the light is the same.
O More electrons would be released.
Photons would come off at higher speeds.
If you then increase the intensity of the 4.5 eV light, you will notice that the photons would come off at higher speeds.
What is intensity of light?
Light intensity refers to the strength or amount of light produced by a specific lamp source.
Intensity of light measures of the wavelength-weighted power emitted by a light source.
Mathematically, the intensity of light source is given as;
I = P/A
where;
P is the power of the incident light (photon energy per second )A is the unit areaIncreasing the light intensity (photon energy per second per unit area) increases the rate at which electrons leave the metal, and the electrons have more kinetic energy.
Thus, if you then increase the intensity of the 4.5 eV light, you will notice that the photons would come off at higher speeds.
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What relationship do you observe between the temperature and density?
Answer:Density is directly proportional to pressure and indirectly proportional to temperature. As pressure increases, with temperature constant, density increases. Conversely when temperature increases, with pressure constant, density decreases.
Explanation:
hope this helped
what is the chemical equation for this?
Answer:
J
Explanation:
Chlorine Gas is Cl2 so if it isnt on the left as that its wrong.
Then on the products see that Fe III means Fe is +3 charge so we have to have 3 Cl to balance it to 0 since each cl as -1 charge.
FInally check if the equation is balanced J is maybe H but its to blurry to tell
PLEASE HELP.
how many grams of K2SO4 are in 1.18x10^24 atoms?
Answer:
Mass = 331.17 g
Explanation:
Given data:
Mass in gram = ?
Number of atoms of K₂SO₄ = 1.18 × 10²⁴ atoms
Solution:
Avogadro number:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
1.18 × 10²⁴ atoms × 1 mol / 6.022 × 10²³ atoms
0.19× 10¹ mol
1.9 mol
Mass of K₂SO₄:
Mass = number of moles × molar mass
Mass = 1.9 mol × 174.3 g/mol
Mass = 331.17 g
how many Nitrogen are in 2AlN
6 How many moles are in a 321 g sample of magnesium?
F 13.2 mol Mg
G 13.4 mol Mg
H 13.6 mol Mg
J 13.8 mol Mg
Answer:
13.4mol of Mg
Explanation:
Given parameters:
Mass of magnesium = 321g
Unknown:
Number of moles = ?
Solution:
The number of moles of a substance is given as;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of Mg = 24g/mol
Insert the parameters and solve;
Number of moles = [tex]\frac{321}{24}[/tex] = 13.4mol of Mg
In which phase is the moon when in the position shown in the diagram?
A) First-Quarter Moon
B) Full Moon
C) Last-Quarter Moon
D) New Moon
PLS HELP!!! Which of the following is NOT a basic assumption of the Kinetic Molecular Theory?
a. The size of the particles is negligibly small
b. The kinetic energy is proportional to the temperature
C. Collisions of particles is elastic
d. The quantity of particles is negligible
Answer:
it might be the second answer
HELP ASAP - How much energy is lost when 80.0 grams of steam at 100.C turns into liquid water at 100.C?
Answer:
Q = 43,000 calories = 180,000 joules = 180 Kilojoules
Explanation:
Heat flow for phase change can be defined as Q = m·ΔHv
ΔHv = Heat of Vaporization for water = 540 calories/gram = 2259 joules/gram = 2.259 Kilojoules/gram
m = mass of object of interest ( in this problem 80 grams steam 100°C converting to 80 grams of water at 100°C
Q = m·ΔHv = 80g x 540 cals/g =43.200 calories x 4.184 joules/cal = 180,748.8 joules (calculator answer) => 180,000 joules (2 sig. figs.) = 180 Kj
What is the mass number of a sulfur (S) atom that has 17 neutrons?
Argue the importance of chemistry to the field of materials science.
(short answer)
Explanation:
Chemistry, however, plays the primary role in materials science because it provides information about the structure and composition of materials. Materials scientists study the structures and chemical properties of various materials to develop new products or enhance existing ones.
Answer:
the other person is right.
Explanation:
What occurs to the kinetic energy when the mass moving object is doubled?
Answer:
Kinetic energy increases.
Explanation:
Kinetic energy is energy you get from moving. The equation for KE depends on mass as well as velocity. If you increase one of these factors, KE will increase too.
do ionic, covalent and metallic bonds form molecular or ionic compounds? HELP PLEASE I WILL MARK BRAINLIEST
Answer:
Ionic compounds contains ionic bond
Like NaCl
Molecular compounds contains covalent bond like H2O
And metals contains metalic bond like in copper
Explanation:
Which of the following is the symbol for an element?
Co2
Ch4
C
H2o
In testing for the presence of lead 2+ ions in solution, a student addes a
solution of sodium nitrate. What will be the conclusion of the test if no
precipitate forms? *
How does one balance an equation?
Answer:
To make both sides of an equation equal, multiply the number of atoms in each element until both sides are equal.
Explanation:
The chemical equation is an equation in which the number of atoms of each element on the product side is equal to the number of atoms of each element on the reactant side. To make both sides of an equation equal, multiply the number of atoms in each of the elements on both the sides until both the sides become equal.
Why is the number of electrons or charge of each ion useful information when predicting the products in replacement reactions?
"The number of electrons / charge of each ion tells about the property of the rection either it is single replacement reaction or double replacement reaction."
What is replacement reaction?
Replacement reactions are extremely significant chemistry phenomena. They are employed in a variety of fields. For example, it can employ electroplating, that is reliant on replacement reaction, to keep iron objects from rusting.
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