Answer:
Mass of NaF in 250 g tube of toothpaste = 100 mg of NaF
Explanation:
Mass of fluoride per gram of toothpaste = 1 mg
From the given data, the fluoride compound that is most often used in toothpaste is sodium fluoride, NaF, which is 45% fluoride by mass, mass of sodium fluoride per gram of toothpaste can be determined as follows:
1 mg of fluoride per gram of toothpaste = 45% total mass of NaF per gram of toothpaste
100% mass of NaF in toothpaste = 100/45 * 1 mg = 2.22 mg of NaF.
Therefore, mass of NaF per gram of toothpaste is 2.22 mg.
The mass of NaF in 250 g of toothpaste is then calculated below:
In 250 g of toothpaste, mass of NaF = 250 * 2.22 mg = 99.9 mg of NaF
Which of the following observations about burning sugar provides evidence of a
chemical reaction?
a. Heat is added to the sugar crystals.
b. The sugar melts and becomes a liquid.
с
C. The temperature of the sugar increases.
d. Gas is produced as the sugar turns black.
1 Pt
А
B
D
Question 12 (1 point)
You notice light pollution in
a.space
b.big cities
c.rural areas
d.our galaxy
Answer:
the answer is D . our galaxy
Answer:
our galaxy of course
What is the percent by weight (w/w%) of sugar in soda? Assume the average mass of sugar in soda is 23.0 g and the total mass is 370.0 g.
The percent by weight (w/w%) of sugar in soda : 6.216%
Further explanationGiven
mass of sugar = 23 g
total mass = 370 g
Required
the percent weight
Solution
%weight = (mass of solute : mass of solution) x 100%
solute = sugar
solution = solvent + solute = water + sugar
percent weight of sugar in soda :
= (23 : 370) x 100%
= 6.216 %
According to the law of conservation of matter, we know that the total number of atoms does not change in a chemical reaction and thus mass is conserved. This
is part of a chemical reaction: hydrogen plus oxygen yields water. Can you complete this model? Reorganize the reactants in order to complete the product side
of the reaction
Your answer:
There is another answer choice with 4 reactants
Answer:
the answer is second option. with 2 models
Explanation:
2H2 + O2 gives 2H2O
so there's two models
There are many important laws and theories in science. Which of the following is a law of science?
A living thing is made of at least one cell.
ОО
An atom is made of electrons orbiting a nucleus.
Gravity will pull two objects toward each other.
Natural selection will change species to fit their environments.
Answer: the answer is C
Explanation:
Answer:C
Explanation:I got it correct
Don’t skip please!!! I need help
Given
Atomic symbol
Required
Atomic composition
Solution
Atomic number = number of protons = number of electrons
Mass Number (A) is the sum of protons and neutrons
Number of protons and Number of Neutrons in nucleus
Number of electrons in the shell
From the picture:
protons = 3
neutrons = 4
electrons = 3
atomic number = protons = electrons = 3
mass number = protons + neutrons = 3+4 = 7
Help pls!!!!!!!!!!!!!!!!!!!!!!!!!!
Answer:
water/d
Explanation:
Which of these is smallest?
cells
atoms
matter
elements
Answer:
atoms
Explanation:
i hope that help you
Answer:
atoms
Explanation:
If 80% of the moths are dark and you have 80 moths, how
many would be dark??
Answer:
the answer is 64 moths are dark
What is the name of the sugar that is created
through photosynthesis?
Nopetose
Glucose
Sucrose
Blooptose
:D
Answer:
Glucose!!
Explanation:
Also keep in mind that the actual sugar produced from photosynthesis is C6H12O6, which is the basis for glucose as well as other complex molecules
Answer:
Glucose
Explanation:
photosynthesis uses the energy from the light to convert carbon dioxide molecules which makes glucose
What does "X" represent in the following symbol?
80
Х
35
Answer:bromine
Explanation:
Predict the chemical formula of the compound that will form when Li and o interact.
Answer:
[tex]Li_2O[/tex]
Explanation:
Hello!
In this case, when looking over the chemical formula of a compound formed when two elements interact, we need to realize about their location in the periodic table; thus, since lithium is a metal and oxygen a nonmetal, we infer lithium turns out the cation and oxygen the anion. Moreover, as the oxidation state of lithium is 1+ and that of oxygen is 2-, we can set up the chemical formula as follows:
[tex]Li^+O^{2-}\\\\Li_2O[/tex]
Best regards!
Will give brainliest to correct answer of this picture:
Answer:
option C : cellular respiration
Explanation:
cellular respiration is taking place in this diagram .
as in respiration food get oxidised to release energy and it releases CO2 and water
It’s a test and only need 2 more problems!!!! Thank you and Appreciate it!!!
Answer:
the molar mass of propane (c3H8) is
12*3+1*8
=36+8=44
what is this for questions 2
Answer:
I think is D
Explanation:
PLEASE MARK ME AS BRAINLIEST
One way to represent this equilibrium is: 2 Al(s) 3 Br2(l)2 AlBr3(s) We could also write this reaction three other ways, listed below. The equilibrium constants for all of the reactions are related. Write the equilibrium constant for each new reaction in terms of K, the equilibrium constant for the reaction above.
The question is incomplete, the complete question is;
Aluminum metal and bromine liquid (red) react violently to make aluminum bromide (white powder). One way to represent this equilibrium is:
Al(s) + 3/2 Br2(l)AlBr3(s)
We could also write this reaction three other ways, listed below. The equilibrium constants for all of the reactions are related. Write the equilibrium constant for each new reaction in terms of K, the equilibrium constant for the reaction above.
1) 2 AlBr3(s) 2 Al(s) + 3 Br2(l)
2) 2 Al(s) + 3 Br2(l) 2 AlBr3(s)
3) AlBr3(s) Al(s) + 3/2 Br2(l)
Answer:
See explanation
Explanation:
We have that; Al(s) + 3/2 Br2(l)AlBr3(s)
So;
Al(s) + 3/2 Br₂(l) = AlBr₃(s)
K = [ AlBr₃] / [ Al] [ Br₂]³/²
K² = [ AlBr₃]² / [ Al ] ² [ Br₂]³
Now;
1) 2 AlBr₃ = 2 Al(s) + 3 Br₂(l) =
K₁ = [ Al ] ² [ Br₂]³ / [ AlBr₃]²
K₁ = ( 1 / K² ) = K⁻²
For the second reaction;
2 ) 2 Al(s) + 3 Br₂(l) = 2 AlBr₃(s)
K₂ = [ AlBr₃ ]² / [ Al ]² [ Br₂ ]³
K₂ = K²
For the third reaction;
3 )
AlBr₃(s) = Al(s) + 3/2 Br₂(l)
K₃ = [ Al ] [ Br₂ ] ³/² / [ AlBr₃ ]
= ( 1 / K ) = K⁻¹
Pls answer this ASAP thank you
Answer:
The anwer is not D the anwer is A
Explanation:
Which process directly moves nutrients from plants to the air
A) Percolation
B) Transportation
C) Assimilation
D) Photosynthesis
Answer:
Plants release oxygen in the process of Photosynthesis
Explanation:
What makes an atom a good conductor?
15 The picture shows Earth’s rotation. Which pattern listed below is caused by Earth’s rotation? A Water cycle processes B Length of shadows C Seasonal temperatures D Weathering and erosion HELP ME
Answer:
jayfeather friend me
Explanation:
Hence it is quite important to understand and learn the processes of the water cycle.
Step 1: Evaporation. The water cycle starts with evaporation. ...
Step 2: Condensation. ...
Step 3: Sublimation. ...
Step 4: Precipitation. ...
Step 5: Transpiration. ...
Step 6: Runoff. ...
Step 7: Infiltration.
A first order reaction has a rate constant of 0.924 at 25 oC. Given that the activation energy is 89.8 kJ/mol, calculate the rate constant at 33.3 oC.
Answer:
[tex]k_2=2.46[/tex]
Explanation:
Hello!
In this case, according to the Arrhenius equation for variable temperature:
[tex]ln(\frac{k_2}{k_1} )=-\frac{Ea}{R}(\frac{1}{T_2} -\frac{1}{T_1} )[/tex]
Given the temperatures to be computed in kelvins and the activation energy, we obtain:
[tex]ln(\frac{k_2}{0.924} )=-\frac{89800J/mol}{8.314J/(mol*K)}(\frac{1}{306.45K} -\frac{1}{298.15K} )\\\\ln(\frac{k_2}{0.924} )=0.981\\\\k_2=0.924*exp(0.981)\\\\k_2=2.46[/tex]
Best regards!
What is the volume in mL of 0.36 mol of carbon dioxide at STP?
Answer:
Zero
Explanation:
Please help asap! Giving brainliest to correct answer.
Three sections of the periodic table are labeled A, B, and C in the image below.
Which of the following statements is most likely true for an element present in section B?
Select one:
a. It is a highly reactive metal.
b. It is an inert gas at room temperature.
c. It may act as an insulator or a conductor.
d. It is a highly reactive liquid at room temperature.
Answer:
C. It may act as an insulator or a conductor.
Explanation:
Group B are the metalloids, so they have properties of both metals and nonmetals.
The statement which is most likely true for an element present in section B is: C. It may act as an insulator or a conductor.
A periodic table can be defined as an organized tabular array of all the chemical elements, which is typically arranged in order of increasing atomic number or number of protons (in rows).
In this diagram, the chemical element that is present in section B of the periodic table is a metalloid.
A metalloid can be defined as a chemical element that are typically intermediate between those of semiconductors, non-metals and metals.
Thus, a metalloid has both chemical and physical properties that are a combination of metals and non-metals or semiconductors.In this context, the statement which is most likely true for an element present in section B is that it may act as an insulator or a conductor because it is a metalloid.
Read more: https://brainly.com/question/17482288
According to the following reaction, how many moles of calcium chloride will be formed upon the complete reaction of 27.9 grams of calcium hydroxide with excess hydrochloric acid? calcium hydroxide (aq) + hydrochloric acid (aq) calcium chloride (aq) + water (l) moles calcium chloride
Answer: 0.377 moles of calcium chloride will be formed.
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} Ca(OH)_2=\frac{27.9g}{74g/mol}=0.377moles[/tex]
The balanced chemical reaction is:
[tex]Ca(OH)_2+2HCl\rightarrow CaCl_2+2H_2O[/tex]
According to stoichiometry :
As 1 mole of [tex]Ca(OH)_2[/tex] give = 1 mole of [tex]CaCl_2[/tex]
Thus 0.377 moles of [tex]Ca(OH)_2[/tex] give =[tex]\frac{1}{1}\times 0.377=0.377moles[/tex] of [tex]CaCl_2[/tex]
Thus 0.377 moles of calcium chloride will be formed upon the complete reaction of 27.9 grams of calcium hydroxide with excess hydrochloric acid
The reaction A→B is to be carried out isothermally in a continuous-flow reactor. Calculate the PFR volume to consume 99% of A (CA = 0.01CA0) when the entering molar flow rate is 5 mol/h (assume pure A), the volumetric flow rate is constant at 10 dm3 /h and the rate is: -rA=3CA 2 [ dm3 /mol•h]
Answer:
Explanation:
From the information above:
The equation for the reactor volume of CSTR is given by the formula:
[tex]V = \dfrac{C_{Ao}V_o - C_A V_o }{-rA}[/tex]
[tex]V = \dfrac{C_{Ao}V_o (1 - 0.01)}{KC_A^2}[/tex]
The reaction rate of A is:
[tex]-r_A = kC_A^2[/tex] and k = 3 dm³/mol.h
replacing the values in the above equation to solve for v;
∴
[tex]V = \dfrac{(0.5 \ mol/dm^3) (10 \ dm^3/h) (1 - 0.01)}{ ( 3 \ dm^3/mol.h) (0.01 \times 0.5 \ mol/dm^3)^2}[/tex]
V = 66,000 dm³
Thus, the reactor volume of CSTR is 66000 dm³
Taking the differential mole balance equation for PFR is as follows:
[tex]\dfrac{d(C_AV_o)}{dV} = -r_A[/tex]
[tex]\dfrac{d(C_AV_o)}{dV} = Kc^2A[/tex]
Taking the integral between initial and final concentrations;
[tex]\dfrac{v_o}{k} \int ^{C_A}_{C_{Ao}} \dfrac{dC_A}{C^2A}= - \int ^V_o \ dV[/tex]
[tex]V = \dfrac{V_o}{K} \Big [\dfrac{1}{C_A}- \dfrac{1}{C_{Ao}} \Big ][/tex]
replace the values in the above equation;
[tex]V= \dfrac{(10 \ dm^3/h) }{(3 \ dm^3/mol.h)}\Big [ \dfrac{1}{0.01(0.5 \ mol/dm^3)} - \dfrac{1}{0.5 \ mol/dm^3} \Big ][/tex]
[tex]\mathbf{V = 66 0 \ dm^3}[/tex]
Thus, the reactor volume of PFR is 660 dm³
compute the mass-specific enthalpy change associated with Nz that is undergoing a change in state from 400 k to 800 k
Answer:
The correct answer is "430 kJ/kg". A further explanation is given below.
Explanation:
The given values are:
T₁ = 400 k
T₂ = 800 k
The average temperature will be:
= [tex]\frac{T_1+T_2}{2}[/tex]
= [tex]\frac{400+800}{2}[/tex]
= [tex]600 \ k[/tex]
From table,
At 600 k the [tex]C p[/tex] will be = 1.075
Now,
⇒ The specific enthalpy = [tex]Cp(T_2-T_1)[/tex]
⇒ [tex]\Delta h=1.075 (800-700)[/tex]
⇒ [tex]=430 \ kJ/kg[/tex]
How many liters of N2 gas are in 2.4 moles at STP?
Answer:
any gas takes up 22.4L per mole so 2.4*22.4=53.76
Explanation:
In 2.4 moles at STP, 53.79 litres of N2 gas are present.
What are moles?Moles are defined as the amount of substance of a system that contain the same number of entities as the number of atoms in 12g of carbon 12.
What is STP?STP is defined as the standard temperature and pressure. At STP, as system has s temperature of zero degree centigrade or 273 Kelvin and the pressure is 1 atm.
PV= nRT
P= 1 atm
V= ?
n= 2.4 moles
R= 0.0821 L atm /K/mol
1 x V = 2.4 x 0.0821 x 273
V = 53.79 litres
Hence, 53.79 litres of N2 gas is present in 2.4 moles at STP.
To learn more about moles and STP here
https://brainly.com/question/9945437
#SPJ2
Determine the mass (in g) of a substance, with a density of 2.26 g/mL, that occupies 350.0 mL.
Answer:
m = 79.1 grams
Explanation:
Given that,
Density, d = 2.26 g/mL
Volume occupies, V = 35 mL
We need to find the mass of the substance. We know that the density of an object is equal to the mass per unit volume. So,
d = m/V
[tex]m=d\times V\\\\m=2.26\ g/mL\times 35\ mL\\\\m=79.1\ g[/tex]
So, the mass of the substance is 79.1 grams.
g) How many grams of aluminum (Al) are present in 2.98 mol of Al?
h) How many moles of Br are there if the sample contained 5.6 x 1024 atoms of Br?
Answer:
26.982 g
i think so..........
Which of the following are made possible by energy transfer from the Sun? Choose all that apply.
A. biofuels
B. nuclear power using uranium
C. wind power
D. hydroelectric power using a dam
This is Really Science but I couldn’t find it but please help ASAP!
