Answer:
1.806 × 10²⁴ atoms
Explanation:
To obtain the number of atoms a substance contain, we have to multiply the number of moles in that substance (n) by Avogadro's number, which is 6.02 × 10²³.
According to this question, a sample of carbon tetrachloride (CCl4) contains 3 moles of the substance. The number of atoms in CCl4 is calculated thus:
number of atoms = 3 × 6.02 × 10²³
number of atoms = 18.06 × 10²³
number of atoms = 1.806 × 10²⁴ atoms.
The sp of strontium carbonate, SrCO3, is 5.60×10−10 . Calculate the solubility of this compound in g/L.
Answer:
3.50 × 10⁻³ g/L
Explanation:
Step 1: Make an ICE chart for the solution of SrCO₃
"S" represents the molar solubility.
SrCO₃(s) ⇄ Sr²⁺(aq) + CO₃²⁻(aq)
I 0 0
C +S +S
E S S
The solubility product constant (Ksp) is:
Ksp = [Sr²⁺] [CO₃²⁻] = S²
S = √Ksp = √5.60 × 10⁻¹⁰ = 2.37 × 10⁻⁵ M
Step 2: Convert "S" to g/L
The molar mass of SrCO₃ is 147.63 g/mol.
2.37 × 10⁻⁵ mol/L × 147.63 g/mol = 3.50 × 10⁻³ g/L
How much energy does an X-ray with an 8 nm (8 x 10-9m) wavelength have?
A. 1.99 x 10-25 J
B. 3.33 x 1016 J
C. 2.48 x 10-17 j
D. 8.28 x 10-26 J
Answer:
it would be option C
Explanation:
Speed of light = 3×10^8m/s
Planck's constant = 6.626×10^-34 Js
Wavelength = 8 x 10^-9 m
Energy = [(3×10^8) * (6.626×10^-34)] / 8 x 10^-9
Energy = [19.878×10^(8-34)] / 8 x 10^-9
Energy = 2.48475 × 10^(-26+9)
Energy = 2.48×10^-17 J
Over time, rocks break down into sediment by wind, water, ice, and/or gravity. This process is commonly referred to as
chemical change
Answer:
Explanation:
Chemical change
Emily spills concentrated sodium hydroxide solution on her lab bench. What she should do first?
Answer:
Explanation: hell noo
Cesium-137 is part of the nuclear waste produced by uranium-235 fission. The half-life of cesium-137 is 30.2 years. How much time is required for the activity of a sample of cesium-137 to fall to 9.32 percent of its original value
Answer:
t(9.32% remaining) = 203 yrs (3 sig. figs.)
Explanation:
All radioactive decay follows a 1st order decay profile. This is defined by the expression ...
A =A₀e^-k·t
A = final activity = 9.32%
A₀ = initial activity = 100%
e = base of natural logs
k = rate constant = 0.693/t(1/2) = (0.693/30.2) yrs⁻¹ = 0.023 yrs⁻¹
t = time of decay = ln(A/A₀)/-k = ln(9.32%/100%)/-0.023 yrs⁻¹
= 203.286637 yrs (calc. ans.)
≅ 203 yrs (3 sig. figs.)
Use the following information to calculate the concentration, Ka and pka for an unknown monoprotic weak acid. (8 pts.) 20.00 mL
Volume of unknown weak acid used : 20.00 mL Total volume of 0.20 M NaOH required to reach the equivalence point: 18.50 mL Initial pH of the weak acid 2.87
Answer:
Concentration: 0.185M HX
Ka = 9.836x10⁻⁶
pKa = 5.01
Explanation:
A weak acid, HX, reacts with NaOH as follows:
HX + NaOH → NaX + H2O
Where 1 mole of HX reacts with 1 mole of NaOH
To solve this question we need to find the moles of NaOH at equivalence point (Were moles HX = Moles NaOH).
18.50mL = 0.01850L * (0.20mol / L) = 0.00370 moles NaOH = Moles HX
In 20.0mL = 0.0200L =
0.00370 moles HX / 0.0200L = 0.185M HX
The equilibrium of HX is:
HX(aq) ⇄ H⁺(aq) + X⁻(aq)
And Ka is defined as:
Ka = [H⁺] [X⁻] / [HX]
Where [H⁺] = [X⁻] because comes from the same equilibrium
As pH = 2.87, [H+] = 10^-pH = 1.349x10⁻³M
Replacing:
Ka = [H⁺] [H⁺] / [HX]
Ka = [1.349x10⁻³M]² / [0.185M]
Ka = 9.836x10⁻⁶
pKa = -log Ka
pKa = 5.01Please help me with this ASAP i I will give you Brainliest
identify the organ system pictured below and state two functions of this system in the body
Answer:
skeletal system
Explanation:
to create and fliter blood and provide frame-work to the human body and support
You are an intermediate product of an industrial process which intends to separate iron from its ore. A well known iron ore is hematite. Which of these ores does not contain iron?
Goethite
Malachite
Siderite
Limonite
Answer:
Malachite
Explanation:
Malachite is a copper carbonate hydroxide mineral, with the equation Cu2CO3(OH)2. This dark, green-joined mineral solidifies in the monoclinic precious stone framework, and frequently shapes botryoidal, sinewy, or stalagmitic masses, in cracks and profound, underground spaces, where the water table and aqueous liquids give the way to synthetic precipitation. So, the answer is malachite. Best of Luck!
The drugs Prilosec and Nexium both contain the same active ingredient. Nexium contains a single enantiomer, but Prilosec is a racemic mixture. Which of the following is probably true regarding 20 mg doses of the two different drugs?
a. both drugs will be equally effective
b. both drugs can be prepared using the same synthetic procedure
c. Nexium will be more effective than Prilosec
d. Prilosec will be more effective than Nexium
Answer:
both drugs will be equally effective
Explanation:
A racemic mixture is a substance that contains a 50/50 mixture of the (+) and (-) enantiomers of an optically active compound.
It is important to note that even if a drug occurs as a racemic mixture, only the biologically active enantiomer will interact with the substrate on which the drug acts. The other enantiomer present is just irrelevant. Similarly, its presence does not affect the biological activity of the active enantiomer.
Hence, both Prilosec and Nexium are both equally effective.
Please write the right question. I’ll mark as brainliest if it’s right
Answer:
The correct answer is - A. alkane and E. Branched.
Explanation:
Alkane is saturated hydrocarbons that are combined with a single bond they can be either linear, branched, or cyclic hydrocarbons. A branched-chain or branched compound is a compound that has alkyl groups bonded to its central carbon chain.
Branched alkanes contain only carbon atoms and hydrogen atoms bonded with these carbon atoms in different branches, with carbons connected to other carbons by single bonds only, but the molecules contain branches.
1. Complete the following chart for the following atoms:
Element
Mass
number
Number of
electrons
Number of
neutrons
Atomic
Number
(number of
protons)
Potassium
16
56
26
What is the atomic symbol (the nuclide) for the isotope with 15 protons and 16
neutrons? Your answer must be in the form shown:
AX
You must show the correct numbers for A and Z
and have the correct symbol (Z). (3 points)
Explanation:
If there are 15 protons, 15 nuclear particles of unit positive charge, then
Z
=
15
. Now
Z
≡
the atomic number
, and you look at your copy of the Periodic Table, and you find that for
Z
=
15
, the element phosphorus is specified.
But we are not finished. Along with the 15 defining protons, there are also 16 neutrally charged, massive nuclear particles, 16 neutrons, and the protons and neutrons together determine the atomic mass. The isotope is thus
31
P
, which is almost 100% abundant, and an important nucleus for
NMR spectroscopy.
1 What direction do
molecules move in?
Answer:
The majority of the molecules move from higher to lower concentration, although there will be some that move from low to high. The overall (or net) movement is thus from high to low concentration.
hope this helps!<3
1. Determine the volume of SO2 (at STP) formed from the reaction of 96.7 mol FeS2 and 55.0 L of O2 at 358 K and 1.20 atm.
4 FeS2(s) + 11O2(g) 2Fe2O3(s) + 8SO2(g)
Answer:
40.0L of SO2 are produced
Explanation:
To solve this question we need to find the moles of O2 using PV = nRT in order to find the moles. Thus, we can find the limiting reactant and the moles (And volume) of SO2 produced as follows:
Moles O2:
n = PV/RT
n = 1.20atm*55.0L / 0.082atmL/molK*358K
n = 2.25 moles of O2.
Clearly, limiting reactant is O2.
The moles of SO2 produced are:
2.25 moles of O2 * (8mol SO2 / 11mol O2) = 1.6351 moles SO2
Volume SO2:
V = nRT/P
V = 1.6351 moles SO2*0.082atmL/molK*358K / 1.20atm
V = 40.0L of SO2 are produced
What is erosion?
A) Weathered materials staying in one place
B) The movement of weathered materials by wind, water or ice
C) New materials on a land form
Answer:
B. The movement of weathered materials by wind, water or ice.
Read excerpt and answer 3 questions I’ll mark brainliest. Pls thank you
Answer:
please also share the excerpt
Explanation:
Thank you
What must happen for ice to melt at a given pressure?
A. The average kinetic energy of the water molecules must decrease.
B. Thermal energy must be transferred to the ice from its
surroundings.
C. The orderliness of the water molecules must decrease.
D. Thermal energy must be transferred from the ice to its
surroundings.
Answer:
D
Explanation:
thermal energy must be transferred from the ice to it's surroundings
Thermal energy is the heat and energy present in the system. The thermal energy must be dissipated from ice to the surroundings to melt and produce liquid. Thus, option D is correct.
What is thermal energy?Thermal energy is present in any substance in the form of energy and heat that depends on kinetic energy, orderliness, randomness, temperature, etc. It is passed from a substance to the surrounding at a lesser temperature.
The ice can melt into a liquid when it loses its thermal energy and heat to the surrounding with increased kinetic energy and releases the temperature to the area with a temperature less than the ice.
Therefore, the heat from ice will get dissipated to the outer environment to melt.
Learn more about thermal energy here:
https://brainly.com/question/11278589
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A diver exhales a bubble with volume of 250 mL at pressure of 2.4 atm and temperature of 15 C. How many gas particulate in this bubble?
Answer:
1.5x10²² particulates
Explanation:
Assuming ideal behaviour, we can solve this problem by using the PV=nRT formula, where:
P = 2.4 atmV = 250 mL ⇒ 250 / 1000 = 0.250 Ln = ?R = 0.082 atm·L·mol⁻¹·K⁻¹T = 15 °C ⇒ 15 + 273 = 288 KWe input the given data:
2.4 atm * 0.250 L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 288 KAnd solve for n:
n = 0.025 molFinally we calculate how many particulates are there in 0.025 moles, using Avogadro's number:
0.025 mol * 6.023x10²³ particulates/mol = 1.5x10²² particulatesAir bags are activated when a severe impact causes a steel ball to compress a spring and electrically ignite a detonator cap. This causes sodium azide (NaN3) to decompose explosively according to the following reaction. 2 NaN3(s) --> 2 Na(s) 3 N2(g) What mass in grams of NaN3(s) must be reacted in order to inflate an air bag to 79.5 L at STP
Answer:
154 g
Explanation:
Step 1: Write the balanced decomposition equation
2 NaN₃(s) ⇒ 2 Na(s) + 3 N₂(g)
Step 2: Calculate the moles corresponding to 79.5 L of N₂ at STP
At STP, 1 mole of N₂ occupies 22.4 L.
79.5 L × 1 mol/22.4 L = 3.55 mol
Step 3: Calculate the number of moles of NaN₃ needed to form 3.55 moles of N₂
The molar ratio of NaN₃ to N₂ is 2:3. The moles of NaN₃ needed are 2/3 × 3.55 mol = 2.37 mol.
Step 4: Calculate the mass corresponding to 2.37 moles of NaN₃
The molar mass of NaN₃ is 65.01 g/mol.
2.37 mol × 65.01 g/mol = 154 g
What volume in mL of 0.220 M HBr solution is required to produce 0.0130 moles of HBr?
Answer: A volume of 59 mL of 0.220 M HBr solution is required to produce 0.0130 moles of HBr.
Explanation:
Given: Moles = 0.0130 mol
Molarity = 0.220 M
Molarity is the number of moles of solute present in liter of a solution.
[tex]Molarity = \frac{moles}{volume (in L)}[/tex]
Substitute the values into above formula as follows.
[tex]Molarity = \frac{moles}{volume (in L)}\\0.220 M = \frac{0.0130 mol}{Volume (in L)}\\Volume (in L) = 0.059 L[/tex]
As 1 L = 1000 mL
So, 0.059 L = 59 mL
Thus, we can conclude that a volume of 59 mL of 0.220 M HBr solution is required to produce 0.0130 moles of HBr.
Calculate the number of representative particles of 0.0391 mol Neon gas.
i need help ASAP !
Answer:
2.35 × 10²² particles
Explanation:
To get the number of particles in a substance, we multiply the number of moles (n) of that substance by Avogadro's number (nA).
That is, we say;
number of atoms = n × 6.02 × 10²³
In this question, Neon gas is said to have 0.0391 moles. The number of atoms in that field.
number of particles = 0.0391 × 6.02 × 10²³
number of particles = 0.235 × 10²³
number of particles = 2.35 × 10²² particles
What is the molar mass of Na2SO4?
O A. 142.04 g/mol
O B. 71.05 g/mol
O c. 238.22 g/mol
O D. 94.04 g/mol
Answer: A. 142.04 g/mol
Explanation:
A 15.0 mL urine from a dehydrated patient has a density of 1.019g/mL. What is the mass of the sample, reported in mg?
Answer:
Mass of sample in mg = 15,285 mg
Explanation:
Given:
Volume of urine sample = 15 ml
Density of sample = 1.019 g/ml
FInd:
Mass of sample in mg
Computation:
Mass = density x volume
Mass of sample in mg = Volume of urine sample x Density of sample
Mass of sample in mg = 1.019 x 15
Mass of sample in mg = 15.285 gram
Mass of sample in mg = 15.285 x 1,000
Mass of sample in mg = 15,285 mg
la. A man was traveling by sie is allowed a maximum of 20kg luggage. The man
weighing 3.5kg, 15kg.2kg and 15kg
Find the excess weight of his luggage.
Express the excess weight as a percentage of the maximum weight allowed
Answer: The excess weight of the luggage is 15.5 kg and its percentage is 77.5%
Explanation:
Given values:
Maximum amount of luggage allowed = 20 kg
Amount of luggage man is carrying = [3.5 + 15 + 2 + 15] kg = 35.5 kg
Excessive weight of the luggage carried = Amount of luggage carrying - Maximum amount of luggage allowed
Excessive weight of the luggage carried = [35.5 - 20] = 15.5 kg
To calculate the percentage of excess weight, we use the equation:
[tex]\% \text{excess weight}=\frac{\text{Excess weight carried}}{\text{Maximum allowed}}\times 100[/tex]
Putting values in above equation, we get:
[tex]\% \text{excess weight}=\frac{15.5kg}{20kg}\times 100\\\\\% \text{excess weight}=77.5%[/tex]
Hence, the excess weight of the luggage is 15.5 kg and its percentage is 77.5%
A transition metal in the fourth period from the following list : Cu, O , Pr, Ag
Answer:
Cu
Explanation:
Groups 3 - 12 (or groups IIA - IIB) of the periodic table contain transition elements. Transaction elements start from period four (4) of the periodic table. The phrase alludes to the fact that the d sublevel is filling at a lower main energy level than the s sublevel that came before it.
The transition elements' arrangement is inverted from the fill order, with the 4 s filled prior to the actual 3 d begins. The transition elements are commonly referred to as transition metals since they are all metals. They are less reactive than the metals in Groups 1 and 2 and have normal metallic characteristics.
From the options given Cu is the only transition metal in the fourth period on the periodic table.
Express as ordinary numbers.
3 x 10^0 =
Answer:
the answer is 3
Explanation:
hope this works
15. Triglycerides, waxes, and steroids are all ___ lipids because they contain only carbon, hydrogen, and oxygen
A. simple
B. methyl esters
C. complex
D. long-chain compounds
Answer:
A. simple
Explanation:
An infant acetaminophen suspension contains 80 mg/0.80 mL suspension. The recommended dose is 15 mg/kg body weight.
How many milliliters of this suspension should be given to an infant weighing 13 lb.
Answer:
0.8853 mL
Explanation:
First we convert 13 lb to kg, keeping in mind that 1 lb = 0.454 kg:
13 lb * [tex]\frac{0.454kg}{1lb}[/tex] = 5.902 kgThen we calculate how many mg of acetaminophen should be given, using the recommended dose and infant mass:
15 mg/kg * 5.902 kg = 88.53 mgFinally we calculate the required mL of suspension, using its concentration:
88.53 mg ÷ (80 mg/0.80 mL) = 0.8853 mLMolecule contains carbon, hydrogen and sulfur atoms. When a sample of 0.535g of this compound is burnt in oxygen, 1.119 g of CO2and 0.229 gof H2O and 0.407g of SO2are obtained.
Calculate its empirical formula.
Answer:
The empirical formula is, C4H4S
Explanation:
Number of moles of carbon = 1.119 g/ 44g/mol = 0.025 moles
Mass of Carbon= 0.025 moles × 12 g/ mole = 0.3 g
Number of moles of hydrogen = 0.229/18g/mol × 2 = 0.025 moles
Mass of hydrogen = 0.025 moles × 1 = 0.025 g
Number of moles of sulphur = 0.407g/ 64 g/mol = 0.0064 moles
Mass of sulphur= 0.0064 moles ×32 = 0.2 g
Now we obtain the mole ratios by dividing through by the lowest ratio.
C- 0.025 moles/ 0.0064 moles, H- 0.025 moles/ 0.0064 moles, S- 0.0064 moles/0.0064 moles
C4H4S
Calculate the molality of a 35.4 % (by mass) aqueous solution of phosphoric acid (H3PO4) (35.4 % means 35.4 g of H3PO4in 100 g of solution)
Answer:
3.6124 m/kg
Explanation:
Molality is calculated as moles of solute (mol) divided by kilogram of solvent (kg). Here, we can find these numbers by using the 35.4%, which gives us 35.4 g of H3PO4 and 100 g of solution to work with.
To go from grams to moles for the phosphoric acid, you need to find the molar mass of the compound or element and divide the grams of the compound or element by that molar mass.
Here, the molar mass for phosphoric acid is 97.9952 g/mol. The equation would look like this:
35.4 g x 1 mol / 97.9952 g = 0.3612422 mol
Next, the 100 g of solvent can easily be converted to 0.1 kg of solvent.
To find the molality, divide the moles of solute and kilograms of solution.
0.3612422 mol / 0.1 kg = 3.6124 m/kg
