Answer:
(a) 1.
(b) 4.
(c) 3.
(d) 2.
Explanation:
Hello,
(a) In this case, we do no take into account the zero digits before the first nonzero digit which is three, therefore it has one significant figure.
(b) In this case, we consider all the given figures since they are all after the first nonzero digit, therefore it has four significant figures.
(c) In this case, we consider all the given figures since they are all after the first nonzero digit including the decimal place, therefore it has three significant figures.
(d) In this case, we consider all the given figures since they are all after the first nonzero digit, therefore it has two significant figures.
Regards.
which of the following is an example of a combustion reaction ?
A. photosynthesis in plants
B. cellular respiration in humans
C. mixing of vinegar and baking soda
D. release of carbon dioxide on heating limestone
Answer:
D. release of carbon dioxide on heating limestone
Answer:
The guy up there is wrong cause i literally just took this test and the answer is B. cellular respiration in humans
Explanation:
Billy is running at a rate of 8 m/s West he ran a total distance of 400 m how long does it take him to complete the distance
Answer:
50 Seconds
Explanation:
400 Divided By 8 Is 50
Answer:
50
Explanation:
Its 50 because 400/8=50
a knowledge of life science is essential for botanists, forest technicians ,park rangers and health care workers true or false
Answer: True
Explanation:
I took the test
Answer:
T
Explanation:
Trust i took the test :p
earthquakes are most common
Answer:
Most earthquakes occur along the edge of the oceanic and continental plates.
Explanation:
And if your question is for the country then it will be Japan
A student measured the volume of water to be 18.5 ml; the actual volume was 17.5 ml. What was the % deviation
Answer:
+5.7%
Explanation:
18.5mL/17.5mL = 1.057 = 105.7% - 100% = 5.7%
Since the measured volume was higher, it is PLUS 5.7%
What is the volume of a sample of mercury having a mass of 1.0 kg if the density of mercury is 13.5g/cm3?
Answer:
volume = 74.07 cm³Explanation:
The volume of a substance given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{Density} [/tex]
From the question
Density = 13.5 g/cm³
We must first convert the mass from kg to g
1kg = 1000 g
mass of mercury = 1000 g
Substitute the values into the above formula and solve
That's
[tex]volume = \frac{1000}{13.5} [/tex]
We have the final answer as
volume = 74.07 cm³Hope this helps you
An unknown element X has the following isotopes: ²⁵X (80.5% abundant) and ²⁷X (19.5% abundant). What is the average atomic mass in amu of X?
Answer:
25.4 amu
Explanation:
Step 1: Given data
Mass of the isotope ²⁵X (m²⁵X): 25 amuAbundance of the isotope ²⁵X (ab²⁵X): 80.5 % = 0.805Mass of the isotope ²⁷X (m²⁷X): 27 amuAbundance of the isotope ²⁷X (ab²⁷X): 19.5% = 0.195Step 2: Calculate the average atomic mass of X
We will use the following expression.
m = m²⁵X × ab²⁵X + m²⁷X × ab²⁷X
m = 25 amu × 0.805 + 27 amu × 0.195
m = 25.4 amu
A 194-g sample of caffeine (C3H10 N4O2) contains 6.02 x 10^23 molecules of
caffeine. If some energy drink contains 210. mg of caffeine, how many molecules of caffeine are present in the drink?
Answer:
6.52×10²⁰ molecules.
Explanation:
We'll begin by converting 210 mg of caffeine to grams (g). This can be obtained as follow:
Recall:
1 mg = 1×10¯³ g
Therefore,
210 mg = 210 mg / 1 mg × 1×10¯³ g
210 mg = 0.21 g
Therefore, 210 mg of caffeine is equivalent to 0.21 g of caffeine.
Finally, we shall determine the number of molecules in 0.21 g of caffeine as follow:
194 g of caffeine contains 602×10²³ molecules.
Therefore, 0.21 g of caffeine will contain = (0.21 × 602×10²³)/194 = 6.52×10²⁰ molecules.
Therefore 0.21 g contains 6.52×10²⁰ molecules.
Thus, we can say that 210 mg (i.e 0.21g) of caffeine contains 6.52×10²⁰ molecules.
Complete each of the definitions with the appropriate phrase. Precision means that ___________measurements are close to____________ Accuracy means that___________ measurements are close to_____________
Answer:
Precision means that independent measurements are close to each other.
Accuracy means that independent measurements are close to a known or accepted value.
Explanation:
Accuracy refers to how close the measurements of a measurement system are to the true value while precision refers to how close the measurements are to each other. In other words, accuracy is the closeness of the value of one or more independent measurements to a true value, and precision is the closeness of two or more values of several measurements to each other.
Both are independent of each other, that is to say that the results in the values of a measurement can be precise and not exact, and vice versa.
So:
Precision means that independent measurements are close to each other.
Accuracy means that independent measurements are close to a known or accepted value.
which of the following correctly described a compound
Answer:
We need the options to answer.
Explanation:
N/A
Given the ion C2O4-2- , what species would you expect to form with each of the following ions?1. K+ _____2. Cu2+_____3. Bi3+_____4. Pb4+______5. NH4+______6. H+______
Answer:
1. K₂C₂O₄
2. CuC₂O₄.
3. Bi₂(C₂O₄)₃
4. Pb(C₂O₄)₂.
5. (NH₄)₂C₂O₄
6. H₂C₂O₄
Explanation:
Hello,
In this case, since the oxidation states are exchanged according to the naming rules, the resulting species are shown below:
1. K₂C₂O₄
2. CuC₂O₄ (here, the +2 of copper and -2 of C₂O₄, are simplified).
3. Bi₂(C₂O₄)₃
4. Pb(C₂O₄)₂ (here, the +4 of lead and -2 of C₂O₄, are simplified).
5. (NH₄)₂C₂O₄
6. H₂C₂O₄
Regards.
Sort these molecules into the appropriate bin according to their polarity.Drag the appropriate items to their respective bins.HBr CO2 BF3 H2 CH4 NH3Polar Non polar
Explanation:
Generally, polar molecules contain polar bonds that arise as a result of the difference in electronegativities of the elements in the molecule. In most instances, molecules containing a metal and a non metal are polar in nature.
HBr - This molecule has two opposite sides of polarity, a group 1 and group 7 element. It is polar
CO2 - The bond between C and O is polar however, there is a cancellation of the polar bonds due to how the atoms are arranged. It is non polar.
BF3 - There is no net dipole (separation of charges) in this compound hence it is non polar.
H2 - Covalent molecules made up of only one type of atom are non polar.
CH4 - This is non polar as the difference in electronegativities between C and H is not great enough to form a dipole.
NH3 - The polar bonds (N-H) do not cancel each other out. Hence this molecule is polar.
What is the main purpose of a leaf
Explanation:
for respiration(exchange of gases)
Actually, all leaves have the same structure. The main purpose is to carry the photosynthesis out, that provides food that needs to survive. :)
100. cal of heat are added to 18.0 g of ethanol (0.581 cal/g °C) originally at 23 °C. The final temperature is ____________.
Answer:
Final temperature is 32.56 °C
Explanation:
The specific heat of a substance is the amount of heat required to raise the temperature of 1g of the substance by 1°C.
The following equation/formula is used;
Q = m × c × ΔT
Where; Q= amount of heat supplied
(cal)
M= mass of ethanol (g)
C= specific heat of ethanol
(cal/g °C)
ΔT= change in temperature (°C)
i.e. (final temperature - initial
temperature)
According to the question, Q= 100 calories (cal), M= 18g, C= 0.581 cal/g °C, initial temperature = 23°C, final temperature = ?
Hence, we insert our values into the equation;
Q = m × c × ΔT
ΔT = Q/mc
(Final T - Initial T) = Q/mc
(Final T - 23) = 100/ 18 × 0.581
(Final T - 23) = 100/10.458
Final T - 23 = 9.562
Final T = 23 + 9.562
Final T = 32.562
Hence, the final temperature of ethanol is 32.56°C
graph results on a grid x 0, 10, 20, 30, 40, 50, 60, 70 and y 0,2,6,15,6,3,1,0
1. What are the 5 senses you use
during the 1st step Scientific
Method observation?
Answer:
Sight, hearing, taste, touch, and smell
Explanation:
During your future endeavors in chemistry you will inevitably do a bunch of acid-base problems. Of the strong bases above, calcium hydroxide, strontium hydroxide, and barium hydroxide often trick students into making small mistakes. Why do you think that is the case? a. There is only half a mole of hydroxide per mole of compound. b.They are actually acidic rather than basic. c. Nothing special about these, all acid-base is confusing! d. There are two moles of hydroxide for each mole of these compounds.
Answer:
d. There are two moles of hydroxide for each mole of these compounds.
Explanation:
calcium hydroxide, strontium hydroxide, and barium hydroxide all have two hydroxide compunds. the difference between each of these compounds is they all contain a different element along with hydroxide.
Neil Bohr's model of the atom suggested that electrons are found in distinct paths. Question 11 options: True False
Answer:
true
Explanation:
What are non-examples of a nucleus
Answer:n a red blood cell, the control center is the nucleus. A mitochondria is not a nucleus. It is another organelle that produces energy for the cell.
Explanation:
What is the hydrogen ion concentration of a solution with pH 5.60?
Answer:options
Explanation:
The solar wind is made up of ions, mostly protons, flowing out from the Sun at about 400 km/s. Near Earth, each cubic kilometer of interplanetary
space contains, on average, 6 x 10^15 solar-wind ions.
How many miles of ions are in a cubic kilometer of near- Earth space?
Answer:
There are [tex]6\times 10^{12}[/tex] miles of ions in a cubic kilometer of near-Earth space.
Explanation:
In this context, we must be clear on stating that words miles is a synonym for thousands. In other words, the question may be rewritten to this form: How many thousand of ions are in a cubic kilometer of near-Earth space? In engineering notation, a thousand is represented by:
[tex]x = 10^{3}[/tex]
As we know the average quantity of solar-wind ions in a cubic kilometer of interplanetary space near Earth, we need to make quick conversion to determine the quantity of miles of ions by this formula:
[tex]y = n\cdot 10^{-3}[/tex]
Where:
[tex]n[/tex] - Quantity of solar-wind ions, measured in units.
[tex]y[/tex] - Quantity of solar-wind ions, measured in thousands (or miles).
If we know that [tex]n = 6\times 10^{15}\,units[/tex], then:
[tex]y = (6\times 10^{15}\,units)\cdot \left(10^{-3}\,\frac{miles}{unit} \right)[/tex]
[tex]y = 6\times 10^{12}\,miles[/tex]
There are [tex]6\times 10^{12}[/tex] miles of ions in a cubic kilometer of near-Earth space.
Which of the following statements would be the hypothesis most easily tested? a) Oak trees grow tallest between temperatures of 10 and 40 degrees Celsius. b) All organisms are made of cells c) An invertebrate is an animal without a backbone or an internal skeleton d) If life were to exist on another planet, that life would also be composed of carbon compounds.
Answer: a) Oak trees grow tallest between temperatures of 10 and 40 degrees
Explanation:
This hypothesis is specific, can be tested (though perhaps not easily), and is well set up.
Hope this helps! :)
A hot needle sinks when put on the surface of cold water. Will a cold needle float or sink in warm water?
Answer:
sink
Explanation:
The Intermolecular force of attraction exists within the water molecule. This type of intermolecular force of attraction is known as a hydrogen bond. A hydrogen bond is a dipole-dipole intermolecular attraction that occurs when hydrogen is covalently bonded to highly electronegative elements of a small atomic size.
When the heat is applied to this intermolecular force, the heat disrupts the intermolecular force, and the surface tension is being broken. This is what caused a hot needle to sink when placed in cold water. But when a cold needle is placed on the surface of warm water, the cold needle will not break up the warm water's surface tension. As a result, the cold need sinks in the warm water.
What will be the charge of the ion formed from each of these atoms ?
Si14, As33, Mg12, Rb37, F9, Ge32, Sn50
Answer:
Si14- Si^4+
As33- As^3-
Mg12- Mg^2+
Rb37- Rb^+
F9- F^-
Ge32- Ge^4+
Sn50- Sn^2+, Sn^4+
Explanation:
The elements shown in the answer have their common ions written beside them.
Silicon mostly forms positive ions in oxyacids and complex ions. Arsenic mostly forms its anion. Magnesium forms only the +2cation just as rubidium only forms the +1 cation. The fluoride ion is F^- while tin may for a +2*or +4 cation. Germanium usually forms the +4 cation.
a person loses 2.70 lb in two weeks. how many grams did they lose?
Answer:
1224.7
Explanation:
Each lb is 453.59
Based on the conversion factor, a person loses 2.70 lb in two weeks loses 1225.8 g
How can we concer from pounds, lb to grams?The conversion factor from pounds to grams is given as follows:
1 pound = 454 gTherefore, 2.70 pounds can be converted to grams as follows:
270 lb = 2.70 × 454 g/ 1 lb
270 lb = 1225.8
Thus, a person loses 2.70 lb in two weeks loses 1225.8 g
Learn more about pounds and grams at: https://brainly.com/question/1121265
What should the ^14_6C content (in percent of y0) of a fossilized tree that is claimed to be 3000 years old?
Answer:
The current mass fraction of [tex]^{14}_{6} C[/tex] should be approximately 68.8 percent.
Explanation:
[tex]^{14}_{6} C[/tex] is a radioactive isotope with a halflife of 5568 years. The decay of any radioisotope is modelled after the following ordinary differential equation:
[tex]\frac{dm}{dt} = -\frac{m}{\tau}[/tex]
Where:
[tex]m[/tex] - Current mass of the isotope, measured in grams.
[tex]\tau[/tex] - Time constant, measured in years.
The solution of this equation is of the form:
[tex]m(t) = m_{o}\cdot e^{-\frac{t}{\tau} }[/tex]
Where:
[tex]t[/tex] - Time, measured in years.
[tex]m_{o}[/tex] - Initial mass of the isotope, measured in grams.
The time constant can be found as a function of halflife ([tex]t_{1/2}[/tex]):
[tex]\tau = \frac{t_{1/2}}{\ln 2}[/tex]
If [tex]t_{1/2} = 5568\,yrs[/tex] and [tex]t = 3000\,yrs[/tex], the mass fraction of [tex]^{14}_{6} C[/tex] is:
[tex]\tau = \frac{5568\,yrs}{\ln 2}[/tex]
[tex]\tau \approx 8032.926\,yrs[/tex]
[tex]\frac{m(3000\,yrs)}{m_{o}} = e^{-\frac{3000\,yrs}{8032.926\,yrs} }[/tex]
[tex]\frac{m(3000\,yrs)}{m_{o}} \approx 0.688[/tex]
The current mass fraction of [tex]^{14}_{6} C[/tex] should be approximately 68.8 percent.
Compounds and solutions are different because
A.only compounds are a form of matter.
B.compounds are pure substances while solutions are not.
C.a compound can be physically separated.
D.only compounds have uniform composition.
Answer:
only compound have uniform compositiob
A student was asked to separate a mixture of chemicals. The weight of each component within the mixture is as follows: potassium bromide 2.53g and 0.760g barium sulfate. What is the percentage of barium sulfate within the mixture?
Answer:
a
Explanation:
f
The percentage of barium sulphate within the mixture is 23.1 %.
We have a mixture of barium sulfate and potassium bromide.
We have to determine the percentage of barium sulfate within the mixture.
What is a Mixture ?A mixture is a material made up of two or more different chemical substances which are not chemically bonded to one another.
According to the question -
Mass of barium sulfate = 0.760 g
Total mass of mixture = 0.760 + 2.53 = 3.29 g
Therefore, the percentage of barium sulfate within the mixture -
0.760/3.29 x 100 = 23.1 %
Hence, the percentage of barium sulphate within the mixture is 23.1 %.
To solve more questions on Percentage composition, visit the link below-
https://brainly.com/question/18184070
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Categorize each property as either physical or chemical.
Physical Properties
Chemical Properties
melting point
color
density
flammability
corrosiveness
electrical
reactivity with acids
hardness
Answer:
Physical properties are the properties of a substance that can observed and measured without altering the identity of the substance. Examples of physical properties according to the above question are color, hardness, malleability, electrical conductivity, density, melting point.
Chemical properties on the other hand are the properties of a substance that describes the ability of the substance to undergo chemical reactions based on its composition. Examples include reactivity with acids, flammability.
In other words, to identity a chemical property of a substance we check its ability to be change into a different state via chemical reaction. Rusting of iron is a good example of chemical property.
So therefore, categorizing the properties we have;
Physical properties Chemical Properties
Melting point Flammability
Color Reactivity with acids
Density Corrosiveness
Electrical conductivity
Hardness
Answer:
Physical: Melting Point, Color, Conductivity, Boiling Point
Chemical: Susceptibility to rust, flammability
Explanation:
Give the names of the cation in each of the following compounds: a. CuS b. Ag2SO4 c. Al(ClO3)3 d. CO(OH)2 e. PbCO3.
Answer:
a. Cu2+ (Copper (II) ion ) b. 2Ag+ ( Silver ion) c. Al3+ (Aluminium (III) ion) d. Co2+ ( Cobalt (II) ion) e. Pb2+ ( Lead (II) ion )
Explanation:
Cations are positively charged ions.
In the question given;
CuS , known as Copper (ii) Sulphide, has Cu2+ (Copper (II) ion ) as the Cation.
Ag2SO4, Known as Silver Sulfate, has 2Ag+ ( Silver ion) as the Cation.
Al(ClO3)3, known as Aluminium Chlorate, has Al3+ (Aluminium (III) ion), as the Cation.
Co(OH)2, known as Cobalt(II) Hydroxide, has Co2+ ( Cobalt (II) ion) , as the Cation.
PbCO3, known as Lead(II) Carbonate, has Pb2+ ( Lead (II) ion ), as the Cation.