Explanation:
I think the answer is metric system of units
because it is the most widely used system of units and its use in both science and business.
How long does it take for 87.5 % of each isotope to decay?
(The isotopes are below)
Krypton-73= 27 seconds
Krypton-74= 11.5 minutes
Krypton-76= 14.8 hours
Krypton-81= 2.1 x 10^5 years
Answer:
Kr-73 = 23.625 sec
Kr-74 = 10.0625 minutes (603.75 seconds)
Kr-76 = 12.95 hours (777 minutes)
Kr-81 = 1.8375 * 10^6 years
Explanation:
What you do is multiply each of those amounts by 7/8.
27 * 7/8 = 189/8 = 23.625
23/2 * 7/8 = 161/16 = 10.0625
74/5 * 7/8 = 518/40 = 259/20 = 12.95
210000 * 7/8 = 1470000/8 = 183750 = 1.8375 * 10^6
An element's atomic mass does not Include the mass of Its.
electrons
protons
neutrons
Answer:
The correct option would be 'electrons
Explanation:
5. Where are red blood cells produced?
10 points
O a. in the heart
b. in the blood vessels
c. in bone marrow
O d. in the plasma
Answer:
C
Explanation:
it's produced in the bone marrow
When magnesium is heated in air, the product formed is heavier than the original ribbon. On the other hand when potassium magnate (7) is heated in air, the product formed is light. Explain the different observation
Answer:
See the answer below
Explanation:
When magnesium is heated in air, the element combines with oxygen to form a compound known as magnesium oxide according to the following equation:
[tex]2Mg(s) + O_2 (g)--> 2MgO (s)[/tex]
Hence, the product formed - a combination of magnesium and the oxygen component of air - is heavier than the original magnesium ribbon.
On the other hand, potassium manganate (7) is heated in air and decompose to form potassium manganate (6), manganate oxide, and oxygen gas according to the following equation:
[tex]2KMnO_4 --> K_2MnO_4 + MnO_2 + O_2[/tex]
Hence, the final product formed is lighter than the original product because oxygen gas has been evolved.
Answer:
During the heating of magnesium in air, it gains mass with the addition of oxygen present in air to form the oxide. However, during the heating of potassium manganate (vii), it decomposes or breaks down to simpler products and oxygen gas is given off.
Explanation:
During the heating of magnesium in air, it gains mass with the addition of oxygen present in air to form the oxide.
The equation for the reaction is given below:
2Mg(s) + O2(g) ---> 2Mg0
The molar mass of the magnesium metal is 24.0 g while the mass of the magnesium oxide is 40.0 g. The total mass of the metal before heating is 24 × 2. + 32 = 48.0 g. The total mass after heating = 48 + 32 = 80.0 g. Therefore, there is an increase in mass.
However, during the heating of potassium manganate (vii), it decomposes or breaks down to simpler products and oxygen gas is given off. The equation for the reaction is given below;
2KMnO4(s) ----> K2MnO4(s) + MnO2(s) + O2(g)
With the evolution of oxygen gas, there's a loss in mass of potassium manganate (vii). Molar mass of KMnO4 is 158.0 g while the mass of K2MnO4 is 197.0 g and that of MnO2 is 87.0 g. The total mass on the right hand side is 2 × 158 = 316.0 g. The total mass on the left-hand side with the exception of the gas evolved is 284.0 g. Therefore, there is a loss in mass.
what is it called when a substance that is dissolved in liquid
Which formula represents a compound containing three atoms? A) HNO3 B)H2O C)LIF D)ZnSO4
Answer:
c actual contains three atom
Solve it plz?tttttttttttttttttttt
GIVING BRAINLEST TO WHOEVER HELPS ME AND GETS THE RIGHT ANSWER.
What is the energy source that powers plate movements ?
A. Magma and lava
B. Earth’s magnetic field
C. The sun
D. Earths not interior
Write your thoughts or ideas about the lesson on types of soil.
Answer:
There are different types of soil in the earth. Those different types of soil helps the earth stay healthy in many ways!! Just like the different layers in the earth. There are so many different layers in the earth so that the plants get the different nutrition they need. Not only that but it cleans the water that soaks in the ground.
There are 6 different types of soil, they are; sandy soil, clay soil, silt soil, peat soil, chalk soil, and loam soil.
Explanation:
Sandy soil
Sandy Soil is light, warm, dry and tend to be acidic and low in nutrients. Sandy soils are often known as light soils due to their high proportion of sand and little clay (clay weighs more than sand). These soils have quick water drainage and are easy to work with. They are quicker to warm up in spring than clay soils but tend to dry out in summer and suffer from low nutrients that are washed away by rain. The addition of organic matter can help give plants an additional boost of nutrients by improving the nutrient and water holding capacity of the soil.
Clay Soil
Clay Soil is a heavy soil type that benefits from high nutrients. Clay soils remain wet and cold in winter and dry out in summer. These soils are made of over 25 percent clay, and because of the spaces found between clay particles, clay soils hold a high amount of water. Because these soils drain slowly and take longer to warm up in summer, combined with drying out and cracking in summer, they can often test gardeners.
Silt Soil
Silt Soil is a light and moisture retentive soil type with a high fertility rating. As silt soils compromise of medium sized particles they are well drained and hold moisture well. As the particles are fine, they can be easily compacted and are prone to washing away with rain. By adding organic matter, the silt particles can be bound into more stable clumps.
Peat Soil
Peat soil is high in organic matter and retains a large amount of moisture. This type of soil is very rarely found in a garden and often imported into a garden to provide an optimum soil base for planting.
Chalk Soil
Chalk soil can be either light or heavy but always highly alkaline due to the calcium carbonate or lime within its structure. As these soils are alkaline they will not support the growth of ericaceous plants that require acidic soils to grow. If a chalky soil shows signs of visible white lumps then they can’t be acidified and gardeners should be resigned to only choose plants that prefer an alkaline soil.
Loam Soil
Loam soil is a mixture of sand, silt and clay that are combined to avoid the negative effects of each type. These soils are fertile, easy to work with and provide good drainage. Depending on their predominant composition they can be either sandy or clay loam. As the soils are a perfect balance of soil particles, they are considered to be a gardeners best friend, but still benefit from topping up with additional organic matter.
Those are the different types of soils with all of their many uses. I hope this helps!!!!! Have a wonderful day!!!
How many grams are in 1.5moles of calcium
Answer: 60.117 g
Explanation: [tex]1.5 mol Ca = \frac{40.078g/mol}{1mol}[/tex] multiply and quit all "mol" and you get the grams
ygyjhu went to the store and bumped into afghsiugshjkds
Answer:
well dont hurt yourself
Explanation:
its not very good to
A hydrated sample of cobalt II chloride has a molar mass of 309.99 g/mol. What is the mole ratio between cobalt II chloride and water?
Explanation:
Let there be 1 mole of CoCl2.
Mass of CoCl2 = 1mol * (129.839g/mol) = 129.839g
Mass of H2O = 309.99g - 129.839g = 180.151g
Moles of H2O = 180.151g / (18g/mol) = 10mol
Hence the mole ratio of CoCl2 to H2O is 1 : 10.
Answer:
[tex]\boxed {\boxed {\sf 1 \ mole \ CoCl_2 \ to \ 10 \ mole \ H_2O}}[/tex]
Explanation:
First, identify the formula of cobalt II chloride: CoCl₂
Next, find the molar mass of CoCl₂. Identify the individual element's mass.
Cobalt (Co): 58.93319 g/molChlorine (Cl): 35.45 g/molSince there is a subscript of 2 after the Cl, we must multiply the molar mass of chlorine by 2
CoCl₂: (58.93319 g/mol) + (2* 35.45 g/mol) = (58.93319 g/mol)+(70.9 g/mol) 129.83319 g/molAssuming the sample is 1 mole, we can subtract the mass we just found from the hydrate sample's mass. This is the mass of the water.
309.99 g - 129.83319 g= 180.15681 gNow, we need to find the number of moles of water. Begin by finding the molar mass of water: H₂O
Hydrogen (H): 1.008 g/mol Oxygen (O): 15.999 g/molSince there is a subscript of 2 after the H, we must multiply the molar mass of hydrogen by 2.
H₂O: (1.008 g/mol *2)+ 15.999 g/mol = (2.016 g/mol)+(15.999 g/mol)=18.006 g/molFinally, divide the mass of the water by the molar mass of water.
180.15681 g / 18.006 g/molNote that the grams or g will cancel.
180.15681 / 18.006 mol = 10.00537654 molThis is roughly 10, so we can round to 10.
≈ 10 mol H₂OSo, the mole ratio is 1 mole CoCl₂ to 10 mole H₂O
Help I’ll give brainlist
Answer:
A, And D
Explanation:
I did this before and i got it right ❤
Which statement best describes an example of selective breeding?
5
A. People control how plants or animals reproduce to get desired
traits.
OB. People use enzymes to cut DNA, copy it, and paste pieces of it
back together.
O. Viruses deliver new genes to a person's cells to treat a genetic
condition.
OD. Living things that do well in an environment pass on their genes to
offspring.
Answer:
Answer is A
Explanation:
this is because selective breeding means selecting plants or animals having desired characteristics and let them breed with each other to reproduce an offspring having desired characteristics from both parents.
Answer:
A
Explanation:
Which is more acidic – milk of magnesia or lemon juice? What is the difference in acidity between the two? (milk of magnesia = pH 10.5, lemon juice = pH 2.5)
Answer:
Lemon juice because it has more of a sour taste to it than a watery taste like milk
Explanation:
Exercise 1.6
4students measered a mass of a piece of metalwhose accurate mass
34. 75 g Their results are 34.2 g, 33.75 g, 35.0 g, and 34.69 g.
a.What is the best estimate for the mass of the piece of metal? Explain why?
b.Explain whether the results are precise or accurate?
class???????????? and which chapter?????????
Animals have to eat other things to get their food, but plants can make it themselves. Plants are known as:
A. consumers
B. producers
C. chloroplasts
D. glucose
Answer:
Producersssssssssss
how many liters are in 20 grams of hydrogen gas?
[tex]\huge\bold{\mathfrak{\purple{A{\pink {n {\green {s{\blue{w{\red{e {\orange {r}}}}}}}}}}}}}[/tex]
Volume of 20 g of hydrogen at normal temperature and pressure (NTP) = 240.55 ml.
[tex]\huge\sf\underline{\underline{\red{❥︎ Thanks}}}[/tex]
Which statement best describes what would happen to an ecosystem once the sun is removed?
A. The functions within the ecosystem will eventually stop & everything will die off.
B. The ecosystem will continue to thrive; it does not need the sun's energy to work.
C. The ecosystem will look for a different source of energy to use.
D. The ecosystem will instantly stop working.
Answer:
A. The functions within the ecosystem will eventually stop & everything will die off.
Explanation:
Everything is dependent on the sun --starting from the bottom of the food chain, the producers. However, we wouldn't die instantly because "Earth retains heat fairly well, so humans wouldn't freeze instantly."
In a laboratory, 30. J of heat was added to a gas piston assembly as the piston did 75 J of work on its surroundings. Calculate E for this system
Answer:
-40J
Explanation:
E= -w+q
E= -75J+30J
E= -40J
Which statement is true of all chemical reactions? They can go in just one direction. They can go in just one direction. They occur only in science labs. They occur only in science labs. They break and reform bonds. They break and reform bonds. They create new elements.
Answer:
They break and reform bonds
Explanation:
Chemical reactions basically refer to the transformation of a substance (reactant) to another substance (products).
So we have;
Reactant --> Product
They can go in just one direction.
This option is wrong, because there are reversible reactions which can go in both directions. That is reactants reactants to form products and products react to form reactants.
They occur only in science labs.
This is wrong because chemical reactions occur in our day to day activities. An example is rusting.
They break and reform bonds.
This option is correct. There is breaking of bonds in the reactants and forming of new bonds in the products.
They create new elements
Atoms or elements are not created nor destroyed in chemical reactions so this option is wrong.
which of the following substance is most likely basic
Answer:
Please provide answer options. :)
Mg + 2 AgNO₃ → Mg(NO₃)₂ + 2 Ag How many grams of magnesium nitrate, Mg(NO₃)₂, are formed when 9.87 moles of silver nitrate, AgNO₃, react?
Mass of Magnesium nitrate formed : 731.86 g
Further explanationA reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.
Reaction
Mg + 2AgNO₃ → Mg(NO₃)₂ + 2 Ag
moles of silver nitrate, AgNO₃ = 9.87
mole ratio AgNO₃ : Mg(NO₃)₂ = 2 : 1, so mol Mg(NO₃)₂ :
[tex]\tt \dfrac{1}{2}\times 9.87=4.935[/tex]
mass of Mg(NO₃)₂(MW=148,3 g/mol) :
[tex]\tt mass=mol\times MW\\\\mass=4.935\times 148,3\\\\mass=731.86~g[/tex]
Why doesn’t the nucleus fly apart?
A strong force - called the strong nuclear force - holds protons and neutrons together in the nucleus.
What happens to brain cells when we sleep?
Answer:
What happens is...
Explanation:
Specifically, it allows your neurons, or nerve cells, to reorganize. When you sleep, your brain's glymphatic (waste clearance) system clears out waste from the central nervous system. It removes toxic byproducts from your brain, which build up throughout the day. This allows your brain to work well when you wake up.
7th grade science , please don’t get the answer from the internet :(
Answer:
See the answer below
Explanation:
1. Organisms produce energy for cells by chemically breaking down and unlocking the energy locked-up within food materials in a process known as cellular respiration. The unlocked energy is then utilized for the cell's metabolic activities.
2. Cellular respiration can be aerobic or anaerobic.
Aerobic respiration involves the breakdown of carbohydrates in the presence of oxygen to yield energy in the form of ATP while carbon dioxide and water are produced as by-products.
[tex]C_6H_1_2O_6 + 6O_2 --> 6CO_2 + 6H_2O + ATP[/tex]
Anaerobic respiration involves the breakdown of carbohydrates in the absence of oxygen to produce ATP and lactic acid as a by-product. The lactic acid is later oxidized to carbon dioxide and water to prevent it from building up.
[tex]C_6H_1_2O_6 -> 2C_3H_6O_3 + ATP[/tex]
3. Photosynthesis and cellular respiration are both considered metabolic processes that take place in living organisms. However, photosynthesis is peculiar only to green plants and some algae while respiration is common to all living organisms. While photosynthesis is anabolic, that is, it involves the building up of materials; respiration is said to be catabolic because it involves the breaking down of materials.
During photosynthesis, inorganic products are utilized to produce carbohydrates for plants with oxygen gas released as a by-product according to the following equation:
[tex]6CO_2 + 6H_2O --> C_6H_1_2O_6 + 6O_2[/tex]
During respiration, the food taken by living organisms is broken down to unlock the energy in it for metabolic activities according to the following equation:
[tex]C_6H_1_2O_6 + 6O_2 --> 6CO_2 + 6H_2O + ATP[/tex]
The predicted tidal range along an East Coast shoreline is feet. How much should a fisherman expect the tide to rise during the first hour?
A.2 feet
B.1 foot
C.0.5 feet
D 0.8 feet
Answer:
b. 1foot
Explanation:
im not that sure but hope this helps !! happy holidays!!
A 90.00 g sample of Na, CO *xH, O is heated until all of the water is driven
off, forming 32.28 g of the anhydrous salt, Na, Coz. What is the percent by
mass of H,O in the hydrated compound, Na CO, *xH,O?*
The percent by mass of H₂O in the hydrated compound, Na₂CO₃.xH₂O = 64.13%
Further explanationGiven
90 g sample Na₂CO₃.xH₂O
32.28 g Na₂CO₃
Required
The percent by mass of H₂O
Solution
mass of H₂O = mass of sample - mass of the anhydrous salt, Na₂CO₃
[tex]\tt mass~H_2O=90-32.28=57.72~g[/tex]
The percent by mass :
[tex]\tt \%mass~H_2O=\dfrac{mass~H_2O}{mass~sample}\times 100\%\\\\\%mass~H_2O=\dfrac{57.72}{90}\times 100\%\\\\\%mass~H_2O=64.13\%[/tex]
Show, in a step by step fashion, your calculations to determine the percent
by volume of a solution that is made by mixing 50 ml of ethanol with 210
ml of water.
The percent by volume of a solution : 19.23%
Further explanationGiven
50 ml of ethanol
210 ml of water
Required
The percent by volume of a solution
Solution
Percent Volume (% v/v) : volume (ml) of solute/100 ml of solution ⇒ ratio of the volume of the solute to total volume of the solution
[tex]\tt \%solute(v/v)=\dfrac{solute~volume}{solution~volume}\times 100\%[/tex]
solute= Ethanol
solvent=water
Solution = solute+solvent
Total volume of the solution :
[tex]\tt =volume~of~Ethanol+solume~of~water\\\\=50~ml+210~ml\\\\=260~ml[/tex]
Percent by volume :
[tex]\tt \%volume=\dfrac{50}{260}\times 100\%\\\\\%volume=19.23\%[/tex]
what volume (in L) of a 3.95 M potassium chloride solution would be needed to make 325 mL of a 2.76 M solution by dilution
Explanation:
Moles of KCl in new solution = 0.325dm³ * (2.76mol/dm³) = 0.897mol.
Hence volume needed = 0.897mol / (3.95mol/dm³) = 0.227dm³ or 0.227L.
