What does "X" represent in the following symbol?
80
Х
35
Answer:bromine
Explanation:
Two units of distance used by scientists to describe distances in space are the light-year and astronomical unit. Why do scientists use the light-year instead of Astronomical Units to measure the distances between stars?
The speed of sound is too slow.
Telescopes can measure only in light years
Distant stars can only be seen if there is light
The smaller numbers that result from measuring with larger units are easier to use
Answer:
The smaller numbers that result from measuring with larger units are easier to use .
That’s the one, good luck!
The smaller numbers that result from measuring with larger units are easier to use.
Light year is a unit of astronomical distance that measures the distance traveled by light in one year. The distance between stars can also be measured using parsecs.
The equivalent of this distance in various units is written as follows;
1 light year (ly) = 9.5 x 10¹² km = 63,240 AU1 parsec = 3.26 lyUsing light year to represent the unit of distance is more concise because big measurement can be represented easily with small numbers using this large unit.
Thus, we can conclude that the smaller numbers that result from measuring with larger units are easier to use.
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47.4 grams of calcium carbonate (CaCO3) is dissolved in 450 mL of water. What is the molarity of this aqueous solution?
Answer:
[tex]M=1.05M[/tex]
Explanation:
Hello!
In this case, since the formula for the calculation of molarity is defined in terms of moles and volume in liters as shown below:
[tex]M=\frac{n}{V}[/tex]
Whereas the moles are computed by considering the molar mass of CaCO3 (100.09 g/mol):
[tex]n=47.4g*\frac{1mol}{100.09g}=0.4736mol[/tex]
Thus, we obtain:
[tex]M=\frac{0.4736mol}{0.450L}\\\\M=1.05M[/tex]
Best regards!
How many grams of Kr are in 2.00 mol of Kr? (4)
Answer:
1 mole is equal to 1 moles Krypton, or 83.798 grams.
Explanation:
222 g of MTBE (CO(CH3)4) are added to gasoline, resulting in a total volume of 2 L of reformulated gas (RFG). Assume that the density of RFG is 0.70 g/mL, and the density of MTBE is 0.74 g/mL. For a-d, determine the concentration of MTBE in the RFG in the following units?
a. mg/L
b. moles/L
c. % (w/w)
d. % (v/v)
e. What is the % (w/w) oxygen in the RFG due to MTBE?
Answer:
Explanation:
From the information given:
(a)
[tex]Concentration \ in \ mg/L = \dfrac{Mass \ of \ MTBE \ in \ mg}{Total \ volume (in \ L)}[/tex]
[tex]Concentration \ in \ mg/L = \dfrac{222 \times 10^3 \ mg}{22}[/tex]
[tex]Concentration \ in \ mg/L = 111 \times 10^3 \ mg/L[/tex]
(b)
[tex]number \ of \ mole s= \dfrac{mass}{molar \ mass } \\ \\ number \ of \ mole s=\dfrac{222 \ g}{88.15 \ g/mol} \\ \\ \mathbf{= 2.518 mol}[/tex]
(c)
[tex]w/w \ percentage = \dfrac{mass \ of \ MTBE }{mass \ of \ solution (RFG)}\times 100\%[/tex]
[tex]where; \\ \\ mass \ of \ (RFG) = 2L \times 0.70 g/mL \\ \\ mass \ of \ (RFG) = 2000 ml \times 0.70 g/mL \\ \\ mass \ of \ (RFG) = 1400 g[/tex]
∴
[tex]w/w \ percentage = \dfrac{222 \ g}{1400 \ g}\times 100\% = \mathbf{15.8\%}[/tex]
(d)
[tex]Volume of MTBE =\dfrac{mass \ of \ MTBE}{density \ of \ MTBE}[/tex]
[tex]Volume \ of \ MTBE = 300 \ mL\\[/tex]
∴
[tex]v/v\% = \dfrac{volume \ of \ MTBE}{volume \ of \ RFG} \\ \\ v/v\% =\dfrac{300 \ mL}{2000 \ mL}\times 100\% \\ \\ \mathbf{v/v\% = 15.00\%}[/tex]
(e)
[tex]From \the \ given \ information; \\ \\ 2.5184 \ moles\ of \ MTBE contain \ 2.5184 \ mole of oxygen[/tex]
∴
[tex]mass of oxygen MTBE = 2.5284 mol \times 16\ g/mol \\ \\ mass of oxygen MTBE = 40.3 9 \ g\\ \\ mass\ of \ RFG = 1400 g[/tex]
∴
[tex]\% w/w = \dfrac{mass \ of \ oxygen}{mass \ of RFG }=\dfrac{40.22 \ g}{1400 \ g} \times 100\%[/tex]
[tex]\% w/w == 2.88\%[/tex]
Assume That The Density Of RFG Is 0.7 G/mL And The Density Of MTBE Is ... are added to gasoline, resulting in a total volume of 2 L of reformulated gas (RFG). ... Assume that the density of RFG is 0.7 g/mL and the density of MTBE is 0.74 g/mL. Determine the concentration of MTBE in the RFG in the following units (a-d)
David went shopping with his mom for house renovations supplies. They were looking for materials that would conduct electricity. Which material should they buy?
Copper
Glass
Plastic
Wood
Answer:
this will copper this is correct answer
Question asked: David went shopping with his mom for house renovations supplies. They were looking for materials that would conduct electricity. Which material should they buy?
Answer: Copper
Explanation: Copper would be the right answer because that's the only material that would conduct electricity.
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The French Le Surete included an ex-criminal, Vidocq, who put together files describing the individual modus operendi, or the _____, of each criminal.
criminal behaviors
fingerprints
home addresses
relatives who were also criminals
Answer:criminal behavior
Explanation:
Edge 2021
Answer:
Criminal Behavior
Explanation:
The work of which scientist was most essential to the use of radioactive
isotopes in medicine?
A. Antoine-Laurent Lavoisier
B. Robert Boyle
C. Marie Curie
D. John Dalton
Answer:
A
Antoine-Laurent Lavoisier
:D
The scientist was most essential to the use of radioactive isotopes in medicine is " John Lawrence's".
What is radioactive isotopes?The radioactive isotopes of such an element were called radioisotopes. Atoms that have too much energy in their nucleus or even an unstable neutron-proton pair.
It marked the beginning of John Lawrence's lengthy career of service and the first time a radioactive isotope had already been employed in the management of a human illness. His laboratory is regarded as the origin of nuclear medicine, for which he is regarded as its father.
The scientist most essential to the use of radioactive isotopes in medicine is " John Lawrence's".
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what are three things that are considered a chemical change
Answer:
Color change, precipitation, bubbling
Explanation:
Chemical change changes the chemical composition and undergoes a process in which it results as a new substance.
Help pls!!!!!!!!!!!!!!!!!!!!!!!
Answer:
D a compound
Explanation:
Here is the reaction of carbamic acid and ammonia to form an amide and water. There is a scheme of a reversible reaction where carbamic acid reacts with ammonia to give water and an unknown compound. Carbamic acid is H2NCOH with an oxygen atom attached to the carbon atom by a double bond. Ammonia is a nitrogen atom with three H atoms attached. Water is HOH. Draw the amide product of this reaction.
Answer:
See explanation
Explanation:
I have attempted to show the sequence of the reaction between carbamic acid and ammonia to form an amide and water and urea.
The reaction first involves the protonation of ammonia to give ammonium carbamate.
When ammonium carbamate is heated to 130-140 degrees, we obtain urea and water as the final products of the reaction
Fresh milk has a pH of 6.
How do you think the pH
would change as it became
sour? Explain your answer.
Vinegar is sold as % acidity which means a weight/volume or w/v% calculation. The density of acetic acid is 1.05 g/ml and water is (effectively) 1.0 g/ml. Recollect (from CHMY121) the %w/v refers to a solution with a certain mass of additive made up to 100 mL with the addition of (in this case) water; or gramsofsolute100mLsolution The molar mass of Acetic Acid is 60.052 g/mol. What is the molarity of CH3COOH in water of a 5% acidity vinegar solution
Answer:
0.83M is molarity of the solution
Explanation:
In a 5% w/v solution of vinegar there are 5g of acetic acid per 100mL of solution. Or 50g per liter of solution. As molarity is defined as the moles of the solute (Acetic acid) per liter of solution we need to convert the 50g per liter to moles per liter using molar mass of acetic acid:
Molarity:
50g/L * (1mol / 60.052g) = 0.8326moles/L =
0.83M is molarity of the solutionCalculate the molality of an ethylene glycol (C2H6O2) soltuion, that has a molarity of 2.07 M. The density of the solution is 1.02 g/mL. Only enter the numerical value with 3 significant figures in the answer box below. Do NOT type in the unit (m).
Answer:
2.03
Explanation:
Let's assume we have 1 L of the solution:
There would be 2.07 ethylene glycol moles.The solution would weigh (1000 mL * 1.02 g/mL) = 1020 g.With that information we can calculate the molality:
molality = moles of solute / kg of solventmolality = 2.07 moles / (1020 ÷ 1000) = 2.03 mKeep in mind that this is only an estimate, as we used the kg of the solution and not of the solvent.
The molality of an ethylene glycol solution is 2.03 kg.
What is molality?The moles of solute divided by the mass of solvent in kilograms is known as the molality of a solution.
Calculation of molality:
Given that, molarity is 2.07 M
Density is 1.02 g/ml
Step 1: To convert the litre into grams, multiply the quantity by 1000
The weight of the solution is [tex]\bold{1.02 \;g/ml\; \times 1000 = 1020 g}[/tex]
Now, molality = moles of solute is divided by mass of solvent in kilograms.
[tex]\bold{Molality = 2.07 \times \dfrac{1020}{1000} = 2.03\; kg}[/tex]
Thus, the molality of the solution is 2.03 kg
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molality = moles of solute / kg of solvent
molality = 2.07 moles / (1020 ÷ 1000) = 2.03 m
Keep in mind that this is only an estimate, as we used the kg of the solution and not of the solvent.
A sample of iron, which has a specific heat capacity of 0.449 Jg^-1℃^-1, is put into a calorimeter (see sketch at right) that contains 100.0 g of water. The iron sample starts off at container 93.3 °C and the temperature of the water starts off at 22.0 °C. When the temperature of the water stops changing it's 25.7 °C. The pressure remains constant at 1 atm.
Required:
Calculate the mass of the iron sample. Be sure your answer is rounded to 2 significant digits.
Answer:
[tex]m_{iron}=32.1g[/tex]
Explanation:
Hello!
In this case, since the interaction between hot iron and cold water allows the heat transfer from iron to water and therefore we can write up the following energetic equation:
[tex]Q_{iron}+Q_{water}=0[/tex]
Whereas the heat terms can be written in terms of mass, specific heat and temperature change:
[tex]m_{iron}C_{iron}(T_f-T_{iron}) + m_{water}C_{water}(T_f-T_{water}) = 0[/tex]
So we solve for the mass of iron as follows:
[tex]m_{iron} = \frac{m_{water}C_{water}(T_f-T_{water})}{C_{iron}(T_f-T_{iron}) }[/tex]
Now, we plug in the given data to obtain:
[tex]m_{iron} = \frac{-100g*0.449\frac{J}{g\°C} (25.7\°C-22.0\°C)}{0.449\frac{J}{g\°C} (25.7\°C-93.3\°C) }[/tex]
[tex]m_{iron}=32.1g[/tex]
Best regards!
Suppose a disease wipes out most of the fox population in
the food web shown.
Mountain
lion
Deer
Hawk
Fox
Rabbit
Owl
Snake
Green
plant
Mouse
Which two populations are most likely to increase as a result?
A. Mountain lion
B. Mouse
ロロロロ
O C. Rabbit
D. Green plant
If the fox population in the given food web is significantly reduced due to a disease, two populations that are most likely to increase as a result are the populations of A. Mountain lion and C. Rabbit.
The decrease in the fox population can disrupt the balance of the food web. Since foxes are natural predators of rabbits, the reduced presence of foxes would lead to a decrease in predation pressure on rabbits. This would allow the rabbit population to increase because their natural predators are now less abundant. Also, with a decline in the fox population, there would be fewer predators to control the population of smaller animals like mice. Hence, the mouse population could also increase due to reduced predation pressure. The mountain lion population, being a predator higher up in the food chain, may indirectly benefit from the increase in rabbit and mouse populations. The increase in prey availability could potentially lead to an increase in the mountain lion population as they have more food resources available. The green plant population (D) is unlikely to directly benefit from the decrease in the fox population since they are not directly influenced by predation from foxes. Their population dynamics are primarily driven by other factors such as availability of sunlight, water, and nutrient levels. The correct answer is A. Mountain lion and C. Rabbit
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Compare the two shampoo
Answer:
Explanation:
I think you forgot to attach an image here!
Which example is a long-term environmental change?
O La Niña
O EI Nino
O climate change
O small asteroid impact
C
Natural Phenomena that cause climate change
(Need at least 2)
Answer:
1. The Earth's orbit around the Sun is an ellipse, but it does change shape. ...
The tilt in the axis of the Earth is called its obliquity
Explanation:
2.Volcanic eruptions pump out clouds of dust and ash, which block out some sunlight.
12) How many moles of CO can be produced from
10.0 mol of CO2
Answer:
5
Explanation:
There are 2 moles of CO in each CO2. 10 ÷ 2 = 5
how is the massive star born
How many moles of
salt (NaCl) is 28.7
grams?
Answer:
0.491 mol NaCl
Explanation:
Convert from grams to moles using the molar mass of NaCl:
28.7 g NaCl x 1 mol NaCl/58.44 g NaCl = 0.491 mol NaCl
The molar mass (58.44 g) can be found from adding the molar masses of the individual elements (Na and Cl); the g NaCl will cancel out (dimensional analysis), leaving you with mol NaCl.
PLZZZ help asaap plzzz I give brainliest are the following reactions a SYNTHESIS, DECOMPOSITION, COMBUSTION, SINGLE REPLACEMENT or DOUBLE REPLACEMENT reactions?
N2 (g) + 3 H2 (g)→ 2NH3 (l) ______________
2 H2(g) + O2(g--> 2 H2O(g)
Answer:
Synthesis
Explanation:
Two reactants are becoming one product, so it is a synthesis reaction.
Decomposition is the opposite, so when one molecule becomes simpler atoms.
Example: 2NaCl -> Cl2 + Na
Combustion is reaction with a product of water and carbon dioxide.
Example: CH4 + 2O2 -> CO2 + 2H2O
Single displacement is when one atom takes the place of the other.
Example: K + NaCl -> KCl +Na (where K took the place of Na)
Double displacement is like single displacement but it happens twice. Think of it like the atoms exchanging partners.
Example: HCl +NaH -> NaCl + HOH
Answer:
(i) N2(g)+3H2(g) -->2NH3(g) - When the equilibrium changes, the concentrations of all substances involved in the equilibrium must also change. For our equilibrium reaction: N2(g) + 3H2(g) ⇔ 2NH3(g) + Heat
(ii) 2 H2(g) + O2(g) --> 2 H2O(g) - Synthesis Reaction
HENCE BOTH THE REACTIONS COULD BE CLASSIFIED AS SYNTHEYIC REACTION
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Which equation illustrates conservation of mass?
O 1 H2 + 1 O2 + 2 H2O
O 1 H2 + 1 2 + 1 H2O
O 1 H2 + 1 Cl2 +1HCI
O 1 H2 + 1 Cl2 + 2HCI
Answer:
1H₂ + 1Cl₂ → 2HCl
Explanation:
The reaction that illustrates the law of conservation of mass is shown below:
1H₂ + 1Cl₂ → 2HCl
According to the law of conservation of mass "in a chemical reaction, matter is neither created nor destroy but atoms are rearranged".
Therefore, we are expected to the end a reaction with the amount of substance we start with.
Element H Cl
Reactants 2 2
Products 2 2
We see that number of atoms on both sides are the same.
What is the volume in mL of 0.36 mol of carbon dioxide at STP?
Answer:
Zero
Explanation:
How many carbon dioxide molecules should be added to the products side to obey the law of conservation of matter?
Your answer:
A.four
B.One
C.three
D.two
Answer:
four A
Explanation:
Answer: B) One
Explanation: One carbon dioxide molecule should be added to the products side to balance the equation and obey the law of conservation of matter.
Also, just took the test. One is correct.
There diagrams imply that’s
A TISSUEs are always rectangular
B tissues are made up of cells
C Tissues all look the same
D tissues have the same Function
Answer:
b
Explanation:
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PLEASE HELP this is physical science.
Bone age : 22,920 years
Further explanationGiven
Nt = 2.5 g C-14
No = 40 g
half-life = 5730 years
Required
time of decay
Solution
General formulas used in decay:
[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]
t = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
Input the value :
[tex]\tt 2.5=40.\dfrac{1}{2}^{t/5730}\\\\\dfrac{2.5}{40}=\dfrac{1}{2}^{t/5730}\\\\(\dfrac{1}{2})^4=\dfrac{1}{2}^{t/5730}\\\\4=t/5730\rightarrow t=22920~years[/tex]
A 8.15 g sample of hydrogen peroxide (H2O2) decomposes to form water and oxygen. The temperature and pressures conditions in the lab were 21.2oC and 761.4 torr, respectively. The oxygen gas is collected over a sample of water at 21.2oC; the vapor pressure of water at that temperature is 18.9 torr. When the water level inside and outside of the tube is equal the volume of gas is recorded as 176.23 mL. a) Write and balance the equation for the decomposition reaction
Answer: [tex]H_2O_2\rightarrow H_2+O_2[/tex]
Explanation:
Decomposition is a type of chemical reaction in which one reactant gives two or more than two products.
According to law of conservation of mass, mass can neither be created nor be destroyed. Thus the number of atoms of each element must be same on reactant and product side. Thus chemical equations are balanced.
The balanced equation for the decomposition reaction of hydrogen peroxide is:
[tex]H_2O_2\rightarrow H_2+O_2[/tex]
Decomposition is a type of chemical reaction in which a chemical breaks into two or more molecules or atoms. One reactant breaks into two products which can be shown as:
XY----->X + Y
The decomposition reaction of hydrogen peroxide can be written as:
[tex]H_{2}O_{2} = H_{2} + O_{2}[/tex]
According to the mass conserving law the mass can neither be added nor deleted they can just get transferred. For a reaction to be stable the number of atoms on both sides of the reaction should be balanced.Therefore, the balanced chemical reaction of decomposition of hydrogen peroxide will be:
[tex]H_{2}O_{2} = H_{2} + O_{2}[/tex]
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In a disproportionation reaction, the disproportionate substance
A. has exactly one oxidation state.
B. has exactly two oxidation states.
C. has at least three oxidation states.
D. has either one or two oxidation states.
Answer:
The answer is C: has at least three oxidation states.
Explanation:
you're welcome
Answer:
C
Explanation:
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