Answer:
The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.
Explanation:
hope that helps
Find the molar mass of (NH4)2Cr2O7.
Answer: The molar mass of ammonium dichromate is 252.06 g/mol
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Which of the following statements is true? A)If a hypothesis is proven false, a mistake has been made in the experiment.B) The independent variable is what changes as a result of the dependent variable. C) Changes in the independent variable cause changes in the dependent variable. D) Once a hypothesis is proven true, it becomes a theory and cannot be disproved. ANSWER ASAP
Answer:
D
Explanation:
once a hypothesis is proven true, it becomes a theory and cannot be disproved.
Im so glad i got help with this one because i got a hundred bc of someone.
What is the significance of being able to "grow" organs?
Answer:
The significance of being able to "grow" organs is the potential to create new organs to replace the old and worn out ones or any that are missing. This can potentially save lives.
Explanation:
A 42.0g sample of compound containing only C and H was analyzed. The results showed that the sample contained 36.0g of C and 6.0g of H.
Which of the following questions about the compound can be answered using the results of the analysis? (choose 1 option)
A) What was the volume of the sample?
B) What is the molar mass of the compound?
C) What is the chemical stability of the compound?
D) What is the empirical formula of the compound?
Answer:
D) what is the empirical.formular of the compond
Explanation:
this is because we have two elements and to calculate the empiral formula we need to have their masses which is also given
When the internal energy of a material increases,: a) its temperature will rise b) it will go through a phase change c) A and B d) A or B
Answer:
a or b
Explanation:
Answer:
D. A or B
Explanation: The temperature of a substance cannot increase during phase change, so both A and B cannot happen simultaneously. And internal energy is the sum of the microscopic potential and kinetic energies of a substance, which increase with temperature and phase transition.
Calculate the following to the correct number of significant figures 0.0041 cm x 2.00 cm
x 501 cm
Answer:
4.1 cm³
Explanation:
When multiplying, the product must have the same number of significant figures as the factor with the least number of significant figures. 0.0041 has two significant figures, 2.00 has three significant figures, and 501 has three significant figures. The answer will have 2 significant figures.
0.0041 cm × 2.00 cm × 501 cm
= 4.1082 cm³
≈ 4.1 cm³
Maryann and josh left a cup of ocean water in the sun. When they returned a day later only salt was left in the cup. Which best explains what happens to the ocean water in the cu
Answer:
The water was evaporated from the sun only leaving salt in the cup
Explanation:
the sun done its cycle and the salt was left
Maryann and josh left a cup of ocean water in the sun. When they returned a day later only salt was left in the cup because of the evaporation.
What is evaporation?
The evaporation is a process by which an element in liquid sate gets transfer into from its liquid state to gas below the temperature at which the liquid gets boiled liquid water enters the atmosphere as water gets vaporized.
In the following the salt was in liquid state so converts into solid and liquid turns into gaseous state and salt is remained into the cup.
Therefore, Maryann and josh left a cup of ocean water in the sun. When they returned a day later only salt was left in the cup because of the evaporation.
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A 5 gram round ball has a density of 1.25 grams/milliliter. What is the volume of the round ball?
Explanation:
m=5g
density=1.25g/ml
density=m/v
v=m/density=5/1.25
Problem #1 : Radioisotopes are used for a variety of medical purposes including as cancer treatments. Attaching an alpha emitter to an antibody allows for a targeted therapy which can be less damaging to healthy tissue than some other cancer treatments. One such alpha emitter is Astatine 211 (211At) which undergoes LaTeX: \alpha α decay (hence the name, alpha emitter).
1.) What isotope is created by the LaTeX: \alpha α decay of 211At? 2.) How many p+, n0, and e- does it have?
Problem #2 : The grand dream of the protoscience called Alchemy was the transmutation of Lead (Pb) into Gold (Au). Thousands of years later, surely we can do better... after all, Platinum (Pt) is what everyone wants these days. We'll start with an isotope of lead, 209Pb which undergoes LaTeX: \beta β - decay. In reality, that is the end of our tale. However, this is a thought exercise and we can do what we want. Using the different types of radioactive decay described above, but still starting with LaTeX: \beta β - decay, how could we get 209Pb to Pt?
1.) What isotope is created by the LaTeX: \beta β - decay of 209Pb?
2.) Come up with a sequence of radioactive decay steps that would then lead to an isotope of Pt.
3.) What isotope of Pt did you create? How many p+, n0, and e- does it have?
Answer and Explanation: Many nuclei are radioactive, which means they emit particles to become stable. In the process, they also become a different element. There are 3 types of decay:
Alpha decay: it emits a particle of Helium, i.e., emits a particle with 2 as atomic number (Z) and 4 as atomic mass (A);Beta decay: emits an electron: a particle with 0 mass and -1 as atomic number;Gamma decay: emits a high energy form of electromagnetic radiation and it is extremely dangerous and penetrating;Problem #1:
1.) Astatine: Z = 85 and A = 211
Alpha decay: [tex]{{A=211} \atop {Z=85}} \right. At[/tex] ⇒ [tex]{{207} \atop {83}} \right. Bi + {{4} \atop {2}} \right. \alpha[/tex]
The isotope created is Bismuth
Characteristics: Z = 83; e⁻ = 83; n = A - Z = 207 - 83 = 124
The isotope is Bismuth with 83 protons, 83 electrons and 124 neutrons.
Problem #2
1.) Lead: Z = 82 and A = 82
Beta decay: [tex]{{209} \atop {82}} \right. Pb[/tex] ⇒ [tex]{{209} \atop {81}} \right. Tl+{{0} \atop {-1}} \right. \beta[/tex]
The isotope created is talium.
2.) [tex]{{209} \atop {82}} \right. Pb[/tex] ⇒ [tex]{{209} \atop {81}} \right. Tl+{{0} \atop {-1}} \right. \beta[/tex]
[tex]{{209} \atop {81}} \right. Tl[/tex] ⇒ [tex]{{205} \atop {79}} \right. Au+{{4} \atop {2}} \right. \alpha[/tex]
[tex]{{205} \atop {79}} \right. Au[/tex] ⇒ [tex]{{205} \atop {78}} \right. Pt+{{0} \atop {-1}} \right. \beta[/tex]
3.) The isotope created is [tex]{{205} \atop {78}} \right. Pt[/tex].
p⁺ = 78; e⁻ = 78; n = 127
The isotope created ahs 78 protons, 78 electrons and 127 neutrons.
The substance in a ___________mixture can usually be seen and are easily separated
Answer:
Heterogeneous mixture
Explanation:
A heterogeneous mixture is a mixture of two or more chemical substances (elements or compounds), where the different components can be visually distinguished and easily separated by physical means. Examples include: mixtures of sand and water. mixtures of sand and iron filings.
What is the only part of an atom that cannot change (either protons, neutrons, or electrons)?
What role does DNA play in living organisms?
Answer: a nucleic acid that contains the genetic instructions for the development and function of living things
Explanation:
2. How have fossils been preserved over millions of years?
Answer:A fossil is the remains or traces of a once-living plant or animal that was preserved in rock or other material before the beginning of recorded history. ... Fossils of single-celled organisms have been recovered from rocks as old as 3.5 billion years. Animal fossils first appear in rocks dating back about 1 billion years.
Explanation:
Five
Five types of fossils: (a) insect preserved in amber, (b) petrified wood (permineralization), (c) cast and mold of a clam shell, (d) pyritized ammonite, and (e) compression fossil of a fern.
A solid block of substance is 74.0cm x 55.0cm x 35.0cm and has a mass of 5.69 x 105g. (569000)
Assuming that it did not chemically react with water or dissolve in it, would it float in water?
Answer:
No, it would sink in water.
Explanation:
Firstly, note that whether an object will float or sink in water is dependent on the density of the object and the water. To calculate density of the object, volume and mass is required.
According to the question, a solid block of substance is 74.0cm x 55.0cm x 35.0cm i.e. the Length (L), width (W) and height (H) are 74cm, 55cm, and 35cm respectively.
Volume = L × W × H
Volume = 74 × 55 × 35
Volume = 142,450 cm^3
Mass of the solid object = 5.69 x 105g. i.e. 569000g
Density = mass / volume
Density = 569000/142450
Density = 3.99438
The density of the solid object is 3.99g/cm^3
Consider the fact that the Density of water is 1g/cm^3. An object will FLOAT in water if the density is lower than that of water while it will SINK if the density is higher than that of water.
Since the density of the solid object is 3.99g/cm^3, which is higher than that of water (1.0 g/cm^3), the solid object will SINK in water.
Calculate 1.23 m x 0.89 m and give your answer with the correct number of significant figures?
Answer:
1.1m that what I got and it said it was right
The calculation of the given figure to one significant figure is[tex]1.1 m^{2}[/tex]
Significant figures can be regarded as a number of digits that is present in a particular value.Given 1.23 mAnd 0.89 m
If we multiply we have[tex]( 1.23*0.89) = 1.0947[/tex]
Since, there is no definite significant figure given, I will assume one significant figure.To do this we start to count significant figures starting from first non-zero digit to the actual figure we are requested to stop.We can see that 9 is after zero, the we round off that 9 then it will become 1 , Then the value to one significant figure is [tex]1.1m^{2}[/tex]Therefore, the multiplication of the values to one significant figure is [tex]1.1^{2}[/tex]
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Calculate the average speed for an airplane that went a distance of 600 miles in
3 hours
In an exothermic reaction is energy transferred to or from the surroundings?
Answer:
transfer energy to the surroundings
Explanation:
Exo means exit
Atoms of elements in the same group have the same number of . This is why they have similar chemical properties.
Answer:
Same number of electrons in their outer shell.
Explanation:
Whe working out their electronic configuration ( by looking at the atomic number) , one will find out that the number of electrons in their outer shell is also the same so the elements have to lose or gain the same amount of electrons to become stable.
Answer: its , valence electrons I just did it
How do we observe in experiments?
Answer:
by watching and writing down the information that is provided
Explanation:
studying the process of photosynthesis in plants
Answer:photosynthesis is a prosses of making food in plants.
The raw materials that are needed
are water carbondioxide,chlorophyl.
And the products are glucose for the plant and oxygen realesed to the atmosphere.
Which statement refers to the quantum mechanical model? A) Electrons move in a circular path about the nucleus. B) Electrons can lose energy and fall into the nucleus. C) Electrons are in "orbitals", regions of space where there is high probability of being found. D) An electron can move from one circular path to another only when it absorbs or emits energy corresponding to the exact difference between the two energy states.
Answer:
Electrons are in "orbitals", regions of space where there is high probability of being found.
Explanation:
The Wave mechanical model of the atom does not restrict the electrons to certain energy levels only as in the Bohr's model, instead it describes a region around the nucleus called an orbital, where there is a high probability of finding an electron with a certain amount of energy.
Each energy level is composed of one or more orbitals and the distribution of electrons around the nucleus is determined by the number and kind of energy levels that are occupied.
Audrey drove 50 miles in 2 hours. What was her average speed? 25 miles per hour 20 miles per hour 50 miles per hour 100 miles per hour
Answer:
25 miles per hour is the answer.
Explanation:
It is right because I just finished the test and got 100%
A) accelerated upward. B) slowed and then stopped. C) moved at a constant velocity. D) increased its speed rapidly.
Answer:
A because the line is showing accelerated upward.
Explanation:
is being flammable a physical or chemical property?
Answer:
Chemical
Explanation:
The conversion factor 100mL/1 L would be used to change what
Answer:
Liters to milliliters.
Explanation:
Conversion factors are used to convert from one unit to another. The unit you are converting from goes in the denominator, and the unit you are converting to goes in the numerator. Since liters is in the denominator, you are converting from liters to another unit. Since milliliters is in the numerator, you are converting to that unit. Therefore, you would be converting from liters to milliliters.
What are the four categories commonly used to classify chemicals and chemical agents in the graphic communications industry
Answer:
Organic
Plate making
Ink mists
Gas, fumes and dust
Explanation:
the four categories commonly used to classify chemicals and chemical agents in the graphic communications industry are Organic ,Plate making ,Ink mists, Gas, fumes and dust.
Organic refer to those chemicals gotten from living matter and are natural.
Plate making refers to how plates are make and it carry image in the printing process.
Ink mist gotten from ink is use in graphic designs for painting and color indication.
An electron is approximately 0.05% of the mass of a proton. Protons and neutrons each have a mass of 1 amu. Which of the following best describes the relationship between mass and subatomic particles?
A. The mass of an electron is equal to that of a neutron
B. Atomic mass is the total number of protons and electrons
C. A neutron has 0.05% more mass than an electron
D. The nucleus comprises over 99% of the atom's mass
Answer:
D. The nucleus comprises over 99% of the atom's mass.
Explanation:
Which of the following best describes the relationship between mass and subatomic particles?
A. The mass of an electron is equal to that of a neutron. FALSE. The mass of an electron is ≈1/1,840 of that of a neutron.
B. Atomic mass is the total number of protons and electrons. FALSE. Atomic mass is the total number of protons and neutrons.
C. A neutron has 0.05% more mass than an electron. FALSE. A neutron has 0.05% more mass than a proton.
D. The nucleus comprises over 99% of the atom's mass. TRUE. The nucleus comprises protons and neutrons.
What element is in group 2 and period 4?
Answer:
Calcium
Explanation:
What is the benefit to having baby steps in science occur as small bits of evidence accumulate?
If someone could help me I would really appreciate it! Thank you
Answer:
aby steps in science occur as small bits of evidence gradually accumulate. The accumulating evidence lets scientists refine and expand on earlier ideas
Explanation:
The benefit to having baby steps in science occurs as small bits of evidence accumulate is which lets scientists refine and expand on earlier ideas. The correct option is a.
What is science?Science is the subject of learning facts and ideas about the earth and other natural things present on the earth. It constitutes the phenomena and the acts behind the happening of things. They search and contribute to the reason behind something natural.
Science works based on evidence and proof. It describes the theories and facts behind natural things. So taking baby steps in science is essential to make it clear that no facts are left behind. Science always changes because of the changing of things.
Thus, the correct option is a. let scientists refine and expand on earlier ideas.
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Which subatomic particle causes the name of the element to change?
Answer:
Proton
Explanation:
Changing the number of protons in an atom changes the type of atom.