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 energy resource causes the greatest waste disposal concerns?
solar power
nuclear
coal
geothermal power
what kind of crystalline solid is graphite?
Answer:
Covalent-network (also called atomic) solids—Made up of atoms connected by covalent bonds; the intermolecular forces are covalent bonds as well. Characterized as being very hard with very high melting points and being poor conductors. Examples of this type of solid are diamond and graphite, and the fullerenes.
I hope it's helpful!
Answer:
network solid
Explanation:
How many moles are in 3.01 x 10^23 atoms of zinc?
Answer:
What is ^ for?
Explanation:
35.2 J of heat is
applied to 16.0 g
of a substance.
Temp rises by 7.2
K. Specific Heat?
The specific heat : c = 0.306 J/g K
Further explanationGiven
Heat = 35.2 J
Mass = 16 g
Temperature difference : 7.2 K =
Required
The specific heat
Solution
Heat can be calculated using the formula:
Q = mc∆T
Q = heat, J
m = mass, g
c = specific heat, joules / g ° C
∆T = temperature difference, ° C / K
Input the value :
c = Q / m.∆T
c = 35.2 / 16 x 7.2
c = 0.306 J/g K
How to get the density of this unknown liquid?
Answer:
Measure the volume of water poured into a graduated cylinder, then place the object in the water and remeasure the volume. The difference between the two volume measurements is the volume of the object. Now simply divide the mass by the volume to calculate the density of the object.
20 g of Allg is dissolved in water to produce a solution with a concentration of 2.007M. What is the volume of this solution in milliliters?
Answer:
369 ml
Explanation:
Mass of Aluminium (Al) = 20 g
Molar concentration = 2.007M
Molar concentration = Number of moles / Volume
The relationship between mass and number of moles;
Number of moles = Mass / Molar mass
Number of moles = 20 / 27 = 0.741 mol
2.007 = 0.741 / Volume
Volume = 0.741 / 2.007 = 0.369 L
converting to millilitres by multiplying by 1000
Volume = 0.369 * 1000 = 369 ml
Density of water calculation using a 10 mL graduated cylinder
10 mL graduated cylinder + 10 mL unknown liquid (g) 10 mL graduated cylinder (g) Volume of liquid (mL) Density (g/mL)
Trial 1 19.731 9.861 10.0
Trial 2 19.831 9.861 10.0
Trial 3 19.831 9.861 10.0
Trial 4 19.771 9.861 10.0
Trial 5 19.751 9.861 10.0
Required:
Calculate the average density for the gradudated cylinder measurements.
Answer:
Average density of the liquid = 0.992 g/mL
Explanation:
Density = mass/volume
mass of liquid = (mass of liquid + mass of cylinder) - mass of cylinder
Trial 1: mass of liquid = 19.731 - 9.861 = 9.87
volume of liquid = 10 mL
density of liquid = 9.87 g / 10 mL = 0.987 g/mL
Trial 2: mass of liquid = 19.831 - 9.861 = 9.97
volume of liquid = 10 mL
density of liquid = 9.97 g / 10 mL = 0.997 g/mL
Trial 3: mass of liquid = 19.831 - 9.861 = 9.97
volume of liquid = 10 mL
density of liquid = 9.97 g / 10 mL = 0.997 g/mL
Trial 4: mass of liquid = 19.771 - 9.861 = 9.91
volume of liquid = 10 mL
density of liquid = 9.91 g / 10 mL = 0.991 g/mL
Trial 5: mass of liquid = 19.751 - 9.861 = 9.89
volume of liquid = 10 mL
density of liquid = 9.89 g / 10 mL = 0.989 g/mL
Average density = (0.987 + 0.997 + 0.997 + 0.991 + 0.989)/5 = 4.961/5
Average density of the liquid = 0.992 g/mL
Help ASAP please
Which statement best describes the reaction pathway graph for an exothermic reaction but not an endothermic reaction?
It has a hill in the middle that is the highest point.
It has a valley in the middle that is its lowest point.
The reactants are higher in energy than the products.
The products are higher in energy than the reactants.
Answer: C ) The reactants are higher in energy than the products
Explanation:
The enthalpy that is a state variable that identifies the content of heat. Then the change of enthalpy for the exothermic reactions is negative, meaning that the energy of the products is lower than the energy of the reactants.
________ gas is evolved in cathode during the electrolysis of water. 20 points answer fast
Answer:
hydrogen
Explanation:
In electrolysis of water, gas evolved at cathode is hydrogen
14.86 ml + 15.0 ml + 14.980 ml =
Answer:
44.84 ml
Explanation:
14.86
+
15.0
+
14.980
_______
44.84
2. What is the final temperature when a 32.0 g piece of diamond at 33.5°C is heated with 360 J of energy?
(Cp = 0.509
Answer:
55.6 °C
Explanation:
From the question given above, the following data were obtained:
Mass (M) of diamond = 32.0 g
Initial temperature (T₁) = 33.5°C
Heat (Q) required = 360 J
Specific heat capacity (C) of diamond = 0.509 J/gºC
Final temperature (T₂) =?
Next, we shall determine the change in temperature. This can be obtained as follow:
The final temperature can be obtained as follow:
Mass (M) of diamond = 32.0 g
Heat (Q) required = 360 J
Specific heat capacity (C) of diamond = 0.509 J/gºC
Change in temperature (ΔT ) =?
Q = MCΔT
360 = 32 × 0.509 × ΔT
360 = 16.288 × ΔT
Divide both side by 16.288
ΔT = 360 / 16.288
ΔT = 22.1 °C
Finally, we shall determine the final temperature. This can be obtained as follow:
Initial temperature (T₁) = 33.5°C
Change in temperature (ΔT ) = 22.1 °C
Final temperature (T₂) =?
ΔT = T₂ – T₁
22.1 = T₂ – 33.5
Collect like terms
22.1 + 33.5 = T₂
T₂ = 55.6 °C
Therefore, the final temperature is 55.6 °C.
Deforestation happens when people try to provide more:
a) water
b) waste
c) timber
d) oxygen.
Help solve please, it’s due in less than an hour or so.
sorry i can only figure out 1 but the answer is
------------------------------------------------------------------
124
hope you do good on your test :D
6. Describe nuclear fusion reactions as they
occur in the sun.
Answer:
i wish i know
Explanation:
i wish i know
What is the density of an object that has a mass of 28.1g and a volume of 96.2mL? Select the correct answer below: 0.292g/mL 2703g/mL 1.00g/mL 3.42g/mL
Answer:
0.292 g/mL.
Explanation:
From the question given above, the following data were obtained:
Mass of object = 28.1 g
Volume of object = 96.2 mL
Density of object =..?
Density of an object is simply defined as the mass of the object per unit volume of the object. Mathematically, it can be expressed as:
Density = mass / volume
With the above formula, we can obtain the density of the object as follow:
Mass of object = 28.1 g
Volume of object = 96.2 mL
Density of object =..?
Density = mass / volume
Density = 28.1 / 96.2
Density of object = 0.292 g/mL
Thus the density of the object is 0.292 g/mL
True or false questions?
Most metal elements are brittle and do not conduct electricity. True or False
Any element can be identified by counting the protons in its neucleus. True or False
All Earths matter is made from the combination of about 100 elements. True or false
Answer:
1. False 2.True3.True? Unsure
Explanation:
Use the periodic table to select the element that best fits each of the following descriptions.
Noble gas:
O oxygen
O chlorine
Okrypton
Answer:
Krypton
Explanation:
Pls answer this two ASAP PLSSSSSSSS
Answer:
1. aa
2. They have similar DNA
Explanation:
1. According to the question 1, wrinkled seeds (A) are dominant over round seeds (a) in pea plants. This means that, based on the law of dominance proposed by Mendel, wrinkled seeds will be expressed over round seeds in a heterozygous state (Aa).
However, since the round seed phenotype is a recessive trait, it will only be expressed when the alleles for round seeds (a) are the same in the gene i.e. aa genotype.
2. Based on the information in question 2, Ricky, who is working on a family tree for his school project, realizes that his close relatives all look similar in the pictures he collected. This is possible because of the SIMILARITY OF THEIR DNA (genetic material). Note that, relatives are connected by the genes that are inherited from one another, hence, they possess a similar DNA, which is the most valid reason for the resemblance.
Determine the density (in g/mL) of a substance with a mass of 105 g and a volume of 17.6 mL.
Answer:
Density, d = 5.96 g/mL
Explanation:
Given that,
Mass, m = 105 g
Volume, V = 17.6 mL
We need to find the density of the substance. So,
[tex]d=\dfrac{m}{V}\\\\d=\dfrac{105\ g}{17.6\ mL}\\\\d=5.96\ g/mL[/tex]
So, the density of the substance is 5.96 g/mL.
If an oxygen molecule is moving at 4.78 x 104
cm.s-, what is its speed in mi hrl?
Show work please
Answer: 1075.5 mph
Explanation:anything moving at 4.78*10^4 cm/sec
equivalent to
cm —> miles = 1/1.6*10^5
sec —> hr = 1/3600
[4.78*10^4]*3600/1.6*10^5 = 1075.5 mph
52
p3
N?
Br1
CaBr2
Cas
Ca3P2
Cal2
Ca3N2
Cat2
K1
Mg2
Zn2
Fe3
What is the name of the process happening in the picture? How do you know it’s that process? Explain your answer in 2 to 3 complete sentences
a certain kind of pea plant has an allele for tall and an allele for short but its overall phenotype is tall.
Answer:
Tt
Explanation:
T= Dominant tall
t= non-dominant short.
Dominant always shows over non-dominant.
3. A gram food sample is burned completely in a calorimeter that contains 1000. of water The temperature of the water increases 23.65 degrees * C . How many Calories does the food have per gram ?
The food has 23629.64 cal
Further explanationGiven
mass = 1000 g of water
temperature increases 23.65 * C
Required
The energy of the food
Solution
Heat absorbed by water :
Q = m . c . Δt
Q = 1000 g x 4.184 J/g°C x 23.65 °C
Q = 98951.6 J
1 Joules = 0.2388 Calories
98951.6 J = 23629.64 cal
What important function do currents and areas of upwelling provide for living things
in the sea?
Recycles the ocean water through evaporation and precipitation
Brings nutrients up from deeper water for use by organisms
Mixes land and sea organisms to broaden the food web
Allows Earth to have weather and climate changes
(1) Solution A and B are separated by a membrane that is permeable to Mg2 and impermeable to Cl-. Solution A contains 0.1 mM MgCl2, solution B contains 100 mM MgCl2. Mg2 will be at electrochemical equilibrium when solution A is around ____________ mV. 180 mV - 180 mV 90 mV - 90 mV 60 mV - 60 mV
Answer:
90 mV
Explanation:
Faraday constant, F = 96487
Gas constant, R = 8.314
Number of mole of electron transferred, Z = 2
MgCl in solution A, = 0.1 mm
MgCl in solution A, = 100 mm
Using the relation :
E=(RT/ZF) In(Mg out/Mgin)
E = (8.314*298) / (2*96485) * In(100/0.1)
E = (2477.572 / 192970) * 6.9077552
E = 0.0128391 * 6.9077552
E = 0.0886897 V
E = 88.68 mV (approximately 90 mV)
Which of the following is an example of a physical change, but not a chemical change?
Answer:
Boiling Water
Explanation:
Boiling water is an example of physical change and not and not a chemical change because the water vapor still has the same molecular structure as liquid water.If the bubbles were caused by the decomposition of a molecule into gas then boiling would be a chemical change.
Answer:
A chemical change results from a chemical reaction, while a physical change is when matter changes forms but not chemical identity. Examples of chemical changes are burning, cooking, rusting, and rotting. Examples of physical changes are boiling, melting, freezing, and shredding
Explanation:
Label one of the test tubes Fe2+. Add 4 milliliters of iron(II) sulfate to the test tube.
Label the other test tube Fe3+. Add 4 milliliters of iron(III) nitrate to the test tube.
Add 4 milliliters of potassium thiocyanate to each test tube.
Observe the contents of the test tubes, noting any evidence of a chemical reaction. Record your observations in the table. If there is no evidence of a reaction, write “no reaction.”
Answer: A: Has little to no reaction; might turn slightly red in color. B: The liquid grows darker in color to a more reddish tone.
Explanation: I didn’t have the necessary materials to complete the experiment so the teacher told me and I put it in my own words.
David Robinson, a professional basketball
player, is 7 ft, 1.0 in. tall. Convert his height to
centimeters
Show work please
Answer:
215.9 cm
Explanation:
1 foot= 30.5cm
30.5cm times 7 1/12=215.9cm
The given height of David is 7 ft, 1.0 inch, so in centimeters, the height will be 216.4 cm.
What is unit conversion?A conversion factor is a number that is used to multiply or divide one set of units into another. When converting to an equal value, the appropriate conversion factor must be used.
We must convert one unit to another in order to achieve accuracy and avoid measurement confusion.
We do not, for example, measure the length of a pencil in kilometers. In this case, one must convert kilometers (km) to centimeters (cm) (cm).
To convert feet to centimeters, multiply the given foot length by 30.48 cm.
So,
Height in cm will be = 7.1 x 30.48
Height in cm = 216.4cm
Thus, the height of David in centimeters is 216.4 cm.
For more details regarding unit conversion, visit:
https://brainly.com/question/11543684
#SPJ2
You are working to earn enough money for a vacation which costs 2100. Your take-home pay is $16.50/hour, but you only work 4-hour shifts each day. How many days will it take for you to earn enough money to pay for your vacation if all the money you earn goes towards your vacation?
Answer:
32 days.
Explanation:
First we determine how much is made in a day.
16.50 x 4 = 66.
Next, we divide 2100 by 66 to reach our amount of days needed.
2100 / 66 = 31.818181... [81 is what repeats over and over.]
We round this up to the nearest whole number. You can't underpay, so you have to round.
The next whole number would be 32, so our answer is 32 days.