Combustible: Charcoal, straw, cardboard, paper, candle, wood.
Non-combustible: Chalk, stone, iron rod, copper coin, glass.
The half-life of radium-226 is 1590 years. if a sample contains 100 mg, how many mg will remain after 1000 years?
Answer:
[tex]a=64.7mg[/tex]
Explanation:
Hello,
In this case, we need to remember that for the required time for a radioactive nuclide as radium-226 to decrease to one half its initial amount we are talking about its half-life. Furthermore, the amount of remaining radioactive material as a function of the half-lives is computed as follows:
[tex]a=a_0(\frac{1}{2} )^{\frac{t}{t_{1/2}} }[/tex]
Therefore, for an initial amount of 100 mg with a half-life of 1590 years, after 1000 years, we have:
[tex]a=100mg(\frac{1}{2} )^{\frac{1000years}{1590years} }\\\\a=64.7mg[/tex]
Best regards.
1. Which of the following metric relationships is INCORRECT?
A) 1 microliter = 10-6 liters
B) 10 decimeters = 1 meter
C) 103 milliliters = 1 liter
D) 1 gram = 102 centigrams
E) 1 gram = 103 kilograms
Metric relationships 103 ml = 1l, 1g = 102 centigrams and 1g = 103 kilograms are incorrect.
What are metrics?Metrics are a system which is based on decimal values and is used to measure the given quantity. It can be used to measure the length, volume, mass, time, speed, distance etc.
What is kilogram?A metric quantity of mass that is equivalent to one thousand grams A mass of one kilogram weighs a little over two pounds.
1 microliter =[tex]10^{-6}[/tex] liters10 decimeters make up 1 meter.1000 milliliters make up 1 liter. 1 gram has 100 centigrams.1 gram has[tex]10^{-3}[/tex] liters.1 kilogram = 1000 gramHence, option C, D and E are the incorrect options.
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Given: Fe2O3(s) + 3 CO(g) –––––> 2 Fe(s) + 3 CO2(g); ΔH° = –26.8 kJ FeO(s) + CO(g) –––––> Fe(s) + CO2(g); ΔH° = –16.5 kJ determine ΔH° for the following thermochemical equation. Fe2O3(s) + CO(g) –––––> 2 FeO(s) + CO2(g)
Answer:
ΔH° = + 6.2 kJ
Explanation:
Fe₂O₃(s) + 3CO(g) –––––> 2 Fe(s) + 3 CO₂(g); ΔH° = –26.8 kJ ......... ( 1 )
FeO(s) + CO(g) –––––> Fe(s) + CO₂(g); ΔH° = –16.5 kJ .........( 2 )
Multiplying equation ( 2 ) by 2 and subtracting it from ( 1 )
Fe₂O₃(s) + 3CO(g) -2 FeO(s) - 2CO(g) ––> 2 Fe(s) + 3 CO₂(g) - 2Fe(s) - 2CO₂(g) ΔH° = –26.8 kJ - ( 2 x –16.5 kJ )
Fe₂O₃(s) + CO(g) -2 FeO(s)––> CO₂(g) ΔH° = –26.8 kJ + 33 kJ
Fe₂O₃(s) + CO(g) ––>2 FeO(s) +CO₂(g) ΔH° = + 6.2 kJ
Required ΔH° = + 6.2 kJ Ans .
Which statement accurately describes the universe?
Answer: The universe consists of all the energy made by the Sun and stars. The universe consists of all physical objects on Earth and in space. The universe consists of all matter and energy. The universe consists of solar systems which contain galaxies.
Explanation: That's because the Universe does consists of all the energy made by the Sun and Stars. That is how we get our energy is from the Sun and Stars, and the Solar System contains Galaxies.
A bond in which valence electrons are shared is called covalent. is the process of breaking large molecules into smaller ones by adding water. If energy is released when a molecule is broken apart, it is a(n) reaction. The process of building up large molecules from small components is a(n) process. A lipid with four sites lacking hydrogen saturation is a lipid.
Answer:
A bond in which valence electrons are shared is called COVALENT.
HYDROLYSIS is the process of breaking large molecules into smaller ones by adding water.
If energy is released when a molecule is broken apart, it is an EXERGONIC REACTION.
The process of building up large molecules from small components is an ANABOLIC process.
A lipid with four sites lacking hydrogen saturation is a POLYUNSATURATED lipid.
What is 745000 nanometers converted to millimeters?
Answer:
0.745 millimiters
i looked it up on google and this is the right answer
Could somebody please help this is really hard
Answer:
The answers to your questions are given below
Explanation:
1. 3 Na2SO4
Molecules of Na2SO4 = 3
Na (sodium) = 3 x 2 = 6
S (sulphur) = 3 x 1 = 3
O (oxygen) = 3 x 4 = 12
2. 4 Pb(NO3)2
Molecules of Pb(NO3)2 = 2
Pb (lead) = 4 x 1 = 4
N (nitrogen) = 4 x 2 x 1 = 8
O (oxygen) = 4 x 3 x 2 = 24
If a solid has a density of 4.0 g/cm^3, what volume of the solid has a mass
of 24 g? Show work.
Answer:
Volume = 6 cm³Explanation:
Density of a substance is given by
[tex]Density = \frac{mass}{volume} [/tex]
From the question
Density = 4.0 g/cm³
mass = 24g
Substitute the values into the above formula and solve for the volume
That's
[tex]4 = \frac{24}{v} \\4v = 24[/tex]
Divide both sides by 4
v = 6
We have the final answer as
Volume = 6 cm³Hope this helps you
Wk-14
Date
Page
Assignment
1. Calculate the percentage of iron in K3 Fe (CN)
[K= 39, Fe =56, C= 12, N =14]
Answer:
The mass percentage of iron in [tex]\rm K_3[Fe(CN)_6][/tex] (potassium ferricyanide) is approximately [tex]17\%[/tex].
Explanation:
Start by finding the formula mass of potassium ferricyanide, [tex]\rm K_3[Fe(CN)_6][/tex], using relative atomic mass data from the question:
[tex]\begin{aligned} & M(\mathrm{K_3[Fe(CN)_6]}) \\ &\approx 3 \times 39 + 56 + 6 \times (12 + 14) \\ &= \rm 329 \; g \cdot mol^{-1}\end{aligned}[/tex].
In other words, every one mole of [tex]\rm K_3[Fe(CN)_6][/tex] formula units have a mass of approximately [tex]329\; \rm g[/tex].
On the other hand, note that there is one iron [tex]\rm Fe[/tex] atom in every one mole of [tex]\rm K_3[Fe(CN)_6][/tex] formula units. Hence, there would be exactly one mole of iron atoms in every one mole of [tex]\rm K_3[Fe(CN)_6][/tex] formula units. The mass of that one mole of iron atoms is approximately [tex]56\; \rm g[/tex] (again, from the relative atomic mass data of the question.)
Therefore:
[tex]\begin{aligned}& \text{Mass percentage of $\mathrm{Fe}$ in $\mathrm{K_3[Fe(CN)_6]}$} \\ &= \frac{\text{Mass of $\mathrm{Fe}$ in one mole of $\mathrm{K_3[Fe(CN)_6]}$ formula units}}{\text{Mass of one mole of $\mathrm{K_3[Fe(CN)_6]}$ formula units}}\times 100\% \\ &= \frac{M(\mathrm{Fe}) \times (\text{Number of $\mathrm{Fe}$ atoms in each $\mathrm{K_3[Fe(CN)_6]}$ formula unit)}}{M(\mathrm{K_3[Fe(CN)_6]})} \times 100\%\end{aligned}[/tex]
[tex]\begin{aligned}&\approx \frac{1 \times 56\; \rm g \cdot mol^{-1}}{329\; \rm g \cdot mol^{-1}}\end{aligned}[/tex].
what is the mass of 5.3 litres of carbon dioxide gas at STP
Answer:
Explanation:
given volume =5.3 litres
as we know that 1 litre =1 dm3
therefore 5.3 litres =5.3 dm3
now moles =given mass /molar mass
so mass =moles*molar mass
in order to find mass of carbon we need to find moles
therefore moles=given volume/standard volume standard volume at STP is 22.4 dm3
moles= 5.3/22.4
moles=0.236=0.24
now mass of carbon dioxide =moles*molar mass
mass = 0.24*44
mass=10.56kg
do cfcs break down ozone
Answer:
Once in the atmosphere, CFCs drift slowly upward to the stratosphere, where they are broken up. So true.
Hope this helps! （づ￣3￣）づ╭❤～
Select the correct answer. An iron nail is made up of particles. What is true about the particles? A. They move all over the place. B. The force of attraction between them is small. C. The spacing between them is large. D. They stay in place and vibrate.
Answer:
Option B is correct.
Explanation:
Since an iron nail is solid and have very large force of attraction between the particles therefore the particles can't move freely and could only vibrate at it's place.
Answer:
Option B is correct.
Explanation:
Since an iron nail is solid and have very large force of attraction between the particles therefore the particles can't move freely and could only vibrate at it's place.
Two Nitrogen atoms bonded together is what? *
O Atom
O Molecule
Help me please
What is the smallest division on this balance? 1g 0.1g 0.01g 0.001g
Correct Answer: 0.01g
The scales and balances have various divisions and units that define the accuracy of the measurement system. The smallest division on the balance scale is 0.001 gm. This, option D is correct.
What is scale?Scales have been defined as the measurement system that estimates the quantity of the various substances in various units including, centimeters, meters, kilograms, grams, milligrams, liter, milliliters, etc. These units are interconvertible.
1 gram is the while part of the gram unit, 0.1 shows one-tenth part of the gram, 0.01 shows the one-hundredth part of the gram, and 0.001 shows the thousandth part of the gram. one gram is the largest number on the scale and 0.001 gm is the smallest number on the balance.
Therefore, option D. 0.001 gm is the smallest number.
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What type of number is this. Water boils at sea level at 100.0 Celsius.
Answer:
100
Explanation:
answer is to simple why it is 100.0 when you write the number down on your calculator it give you 100 because the last zero does not count
What are SL units ?
Answer:
International System of Units
Definition: A system of physical units ( SI units ) based on the metre, kilogram, second, ampere, kelvin, candela, and mole, together with a set of prefixes to indicate multiplication or division by a power of ten.
Hope this helps!
is air a good conductor of electricity
Answer:
No, air is not a good conductor of electricity.
It is poor conductor.
how can a mixture be separated into pure substances
Mixtures can always be separated again into component pure substances, because bonding among the atoms of the constituent substances does not occur in a mixture. Whereas a compound may have very different properties from the elements that compose it, in mixtures the substances keep their individual properties.
Explanation:
Which actions would increase the rate at which salt dissolves in water? Stir the water. Crush the salt. Use less water. Heat the water. Cool the salt.
Answer:
Crushing or grinding increases the surface area of the salt that is exposed to the molecules of water. Stirring increases the speed at which the particles of salt come in contact with the water molecules.
Make a circle graph for each set of data. Top 5 Most Linked-To Sites on the World Wide Web Site Hits (millions) America Online (www.aol.com) 93.0 Microsoft (www.msn.com) 83.8 Yahoo! (www.yahoo.com) 80.2 Terra Lycos (www.lycos.com) 40.3 About (www.about.com) 36.6 Source: Scholastic Kid’s Almanac, 2001 a. A circle graph. America Online is about 25 percent; Microsoft, 25 percent; Yahoo 23 percent; Terra Lycos, 15 percent; About, 10 percent. c. A circle graph. America Online is about 27 percent; Microsoft, 27 percent; Yahoo 22 percent; Terra Lycos, 12 percent; About, 10 percent. b. A circle graph. America Online is about 12 percent; Microsoft, 10 percent; Yahoo 27 percent; Terra Lycos, 17 percent; About, 23 percent. d. A circle graph. America Online is about 12 percent; Microsoft, 10 percent; Yahoo 25 percent; Terra Lycos, 25 percent; About, 20 percent. Please select the best answer from the choices provided A B C D
Answer:
A
Explanation:
A sample of ground beef contains 21.3% protein and 16.9% fat, both by mass. What mass of this ground beef, in grams, contains 350 Calories? Assume all Calories come from protein and fat.
Answer:
147.5 grams
Explanation:
Let the required mass of ground beef be m .
protein in it = .213 m
fat in it = .169 m
1 gram of protein gives 4 cals .
1 gram of fat gives 9 cals .
cals given by .213 m protein = 4 x .213 m .
cals given by .169 m fat = 9 x .169 m .
4 x .213 m + 9 x .169 m = 350
.852 m + 1.521 m = 350
2.373 m = 350
m = 147.5 grams Ans
How many significant figures are in 1.00 L
Answer:
3 significant numbers
Mr. Krabs created a secret ingredient for a breath mint that he thinks will "cure" the bad breath people get from eating crabby patties at the Krusty Krab. He asked 100 customers with a history of bad breath to try his new breath mint. He had fifty customers (Group A) eat a breath mint after they finished eating a crabby patty. The other fifty (Group B) also received a breath mint after they finished the crabby patty, however, it was just a regular breath mint and did not have the secret ingredient. Both groups were told that they were getting the breath mint that would cure their bad breath. Two hours after eating the crabby patties, thirty customers in Group A and ten customers in Group B reported having better breath than they normally had after eating crabby patties. What is the independent variable?
Answer:
Type of breath mint
Explanation:
The independent variable, in this case, would be the type of breath mint given to each study group.
An independent variable refers to a variable whose variation does not depend on another variable or factor. In research, the independent variable stands alone and the researcher can control or manipulate it in order to measure its effect on some other variables.
In the case of Mr. Krabs, the two types of breath mints administered to the two study groups represent the independent variable. Any differences in the experience of the two study groups can be attributed to the difference in the breath mint taken.
there is an ice cream shop 6 blocks north of your hotel. how many minutes will it take to walk there and back
Answer:
This question is incomplete
Explanation:
This question is incomplete.
However, when all the required data are available, you can use the formula/steps below
Average speed/velocity (m/s) = distance (in metres) ÷ time (in seconds)
Time (in secs) = distance ÷ average speed/velocity
Kindly note that "blocks" is not a standard unit for distance measurement in science, hence the distance (since its a walking distance) must be in metres (or converted to metres if not in metres).
The distance in the formula is the distance from the hotel to the ice cream shop while the average speed is the distance covered per time as s/he walks to the ice cream shop and back. Hence, the answer gotten from the formula above will have to be multiplied by 2 (in order to get the time taken to walk to the ice cream shop and back) because the formula will only provide answer to one trip (time taken to walk to the shop).
After the multiplication mentioned above, the time in seconds should be converted to minutes by dividing the answer in seconds by 60
Which model best represents the modifications to
the theory that Thomson's results made
necessary?
Answer:A
Explanation:
If the pressure of a gas sample is quadrupled and the absolute temperature is doubled, by what factor does the volume of the sample change
Answer:
The new volume of the sample is halved.
Explanation:
Data obtained from the question include the following:
Initial volume (V1) = V
Initial temperature (T1) = T
Initial pressure (P1) = P
Final pressure (P2) = quadrupled = 4P
Final temperature (T2) = doubled = 2T
Final volume (V2) =?
Thus, we can obtain the new volume of the same by using the combined gas equation as shown below:
P1V1 /T1 = P2V2 /T2
P × V/T = 4P × V2/2T
Cross multiply
T × 4P × V2 = P × V × 2T
Divide both side by T × 4P
V2 = (P × V × 2T) / (T × 4P)
V2 = V/2
V2 = ½V
Therefore, the new volume of the sample is halved .
In order to survive, plants absorb sunlight, water, and nutrients from the soil. 1. Does this represent a physical or chemical change? 2. Justify why this is this type of change. What property is this?
please help. fill out the blanks
Which of the following describes the characteristics of a plasma? (3 points) a Particles are packed closely together, have low compressibility, and usually maintain their organized, set shape. b Particles are positively and negatively charged, have high compressibility, and spread out to fill a container. c Particles move around in a semi-organized way, take the shape of a container, and fill a container from the bottom up. d Particles move freely, have high compressibility, and spread out evenly to fill a container.
Answer:
The correct option is;
b. The particles are positively and negatively charged, have high compressibility, and spread out to fill a container
Explanation:
Plasma are gases that contain positively and negatively charged particles. Therefore, plasma flow drift in space such that plasma. like gases has no characteristic shape or volume but takes the shape and fills the entire volume of a container in which it is placed
Other characteristics of plasma are that plasma is a conductor of electricity and magnetic fields can therefore exist in plasma due to the fact that plasma are made of atoms in which part or all of the electrons have been removed leaving the ions to roam freely in a container.
What are the limitations of Bronsted-Lowery concept???
Answer:
There is no limitation at all because that is the basic theory of solution electrolysis
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Limitation of Bronsted Lowey concept:
✭It doesn't describe the acidic and basic nature of organic compound.
✭It also doesn't describe the acidic, basic as well as amphoteric gaseous molecule.
✭According to Bronsted Lowery concept same compound in one reaction act as acid and another reaction act as base so, it is difficult to predict the exact acid or base.