Answer:
Rr
Explanation:
Lead is a toxic metal that affects the central nervous system. A Pb-contaminated water sample contains 0.0012 % Pb by mass. What volume of the water in milliliters contains 100 mg of Pb
Answer:
8.3 × 10³ mL
Explanation:
Step 1: Calculate the mass of water that contains 100 mg of Pb
The concentration of Pb in the sample is 0.0012% by mass, that is, there are 0.0012 g of Pb every 100 g of water. The mass of water that contains 100 mg (0.100 g) of Pb is:
0.100 g Pb × 100 g Water/0.0012 g Pb = 8.3 × 10³ g Water
Step 2: Calculate the volume corresponding to 8.3 × 10³ g of water
Since the solution is diluted, we will assume the density of the sample is equal than the density of water (1 g/mL).
8.3 × 10³ g × 1 mL/1 g = 8.3 × 10³ mL
The volume of the water in milliliters contains 100 mg of Pb is;
V = 8.3 × 10³ mL
Volume of SolutionWe are given the concentration of Pb in the sample as 0.0012% by mass.
That means that there are 0.0012 g of Pb in every 100 g of water.
Thus, the mass of water that contains 100 mg (0.100 g) of Pb is calculated as;
(0.100 g Pb × 100 g of Water)/0.0012 g of Pb = 8.3 × 10³ g of Water
Now, we know that the density of water (1 g/mL) but we are not given the density of the sample.
Thus, since the solution is diluted we can equally say that;
Density of sample = 1 g/mL
Formula for Volume is;
V = mass/density
Thus;
V = 8.3 × 10³ g/1 g/mL
V = 8.3 × 10³ mL
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What is the valency of Aluminium and nitrate in Al(NO3)3 ?
Answer:xl/ck xLKsx
Explanation:sl/cs c/ls
he ______ is the depth in the ocean at which calcareous skeletal material first begins to dissolve. Multiple choice question.
Answer: lysocline
Explanation:
Lysocline is the depth in the ocean at which calcareous skeletal material first begins to dissolve. It is the depth of the ocean whereby the dissolution rate of calcite has a dramatic rise.
Lysocline is also referred to as the transition zone upper bound where the CaCO3 content drops.
A train is accelerating at a rate of 2 m/s. If its intital velocity is 20 m/s,what is its veolcity after 30 seconds
Answer:
80 m/s.
Explanation:
NOTE: This is a physics question. However, the solution to the question given below:
From the question given above, the following data were obtained:
Acceleration (a) = 2 m/s²
Initial velocity (u) = 20 m/s
Time (t) = 30 s
Final velocity (v) =?
The final velocity of the train can be obtained as shown below:
v = u + at
v = 20 + (2 × 30)
v = 20 + 60
v = 80 m/s
Therefore, the final velocity of train is 80 m/s.
name a food that contain an acid
Answer:
name a food that contain an acid
1. nuts
2. dairy
3. grains
3. meat
these are the foods which contains acids.
hope its helps you
have a great day keep smiling be happy stay safe.
Which of these is an example of a chemical change?
Answer:
D. Burning a peice of wood
Explanation:
Because when you burn wood a chemical reaction happenes between the flames and the wood making the wood into ashes.
Hope this helps you :)
The dissolving salt in water is an an example of a chemical change. The correct option is A.
A chemical change, also known as a chemical reaction, is the production of new substances with changing chemical compositions and characteristics.
In water, sodium chloride dissociates into Na+ ions and Cl- ions, which may be described as a chemical process.
The ionic connections between the atoms are broken as salt dissolves. Because the reactant (sodium chloride or NaCl) varies from the products (sodium and chloride ions), a chemical reaction takes place.
Thus, the correct option is A.
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Which has more mass, 2 kg of steel or 5 kg of feather.
Answer:
5 kg of feather
Explanation:
Two magnets are stuck together. What might you have to do to get them to separate?
Explanation:
The easiest method to separating magnets is to slide them apart. When separating magnets keep in mind shear force. Magnets are measured on pull strength, so are up to five times easier to move if they are pushed apart instead of pulled apart. Small magnets slide relatively easily, even without spacers.
Firmly slide them away from each other and far enough apart so that they don't hop back together. Neodymium magnets are quite strong.
What are properties of a magnet?The properties of the magnet are:
Magnets will attract ferromagnetic.Like poles of the magnet repel each other and unlike poles bait each otherThe poles of the magnet are in the team.Thus, slide them away from each other and far enough apart so that they don't hop back together.
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Balance the equation for
__Ca+__Pb(NO3)2—__Pb+__Ca(NO3)2
Answer:
Ca + Pb(NO3)2 → Pb + Ca(NO3)2
Explanation:
This is an oxidation-reduction (redox) reaction:
PbII + 2 e- → Pb0
(reduction)
Ca0 - 2 e- → CaII
(oxidation)
Pb(NO3)2 is an oxidizing agent, Ca is a reducing agent.
Diamond is an allotrope of :
a. carbon b. sillica
c. phosphorus c. Nitrogen
Answer:
carbon
Explanation:
because it is an allotrope of carbon
Answer:
Carbon
Explanation:
its literaly carbon
an organic compound on analysis yielded 2.04g carbon, 0.34g hydrogen, 2.73g oxygen. calculate the empirical formula
Answer:
CH2O
Explanation:
According to this question:
C = 2.04g
H = 0.34g
O = 2.73g
First, we divide the mass value of each element by its atomic mass to convert to moles.
C = 2.04g ÷ 12 = 0.17mol
H = 0.34g ÷ 1 = 0.34mol
O = 2.73g ÷ 16 = 0.17mol
Next, we divide by the smallest mole value (0.17):
C = 0.17mol = 0.17 = 1
H = 0.34mol ÷ 0.17 = 2
O = 0.17mol ÷ 0.17 = 1
The whole number ratio of C,H,O is 1:2:1, hence, the empirical formula is CH2O.
HELPPPPPPPP i accidentally pressed on c
Answer:
a
Explanation:
I'm not completely sure tho veary sorry if it's wrong
Answer:
the answer is C
Explanation:
as the yeast feeds on sugar and yields the ATP per glucose molecule and Carbon dioxide
What does binding energy measure?
A. The forces attracting electrons to a nucleus
B. The repelling forces pushing protons apart
C. The energy used to hold the nucleus together
D. The energy released in radioactive decay
Answer:
C. the energy used to hold the nucleus together
Describe 5 importance matter to undergo changes
Answer:
melting, freezing, sublimation, deposition, condensation, and vaporization. These changes
Explanation:
hope it helps...i dont know if its right but i hope it helps
HELP HELP HELP PLSSS
Answer:
the answer is c kept in blue and with light
What dose science do
Explanation:
Science, any system of knowledge that is concerned with the physical world and its phenomena and that entails unbiased observations and systematic experimentation. In general, a science involves a pursuit of knowledge covering general truths or the operations of fundamental laws.
Identify each as measurement for area, volume, density, time, mass temp, length: ns, 12g/ml,
1.8pm, 250m2 ,325K and 5.4mL and 90kg
Answer:
ns - time
12g/ml - density
1.8pm - length
250m2 - area
325K - temperature
5.4mL - volume
90kg - mass
Explanation:
The unit of measurement is used to identify what a measurement is. It is very important to place a specific unit for each measurement made as it distinguishes them from one another. In this question, various measurements were given, which can be identified using their units.
- ns is measurement for time because seconds (s) is its unit
- 12g/ml is measurement for density because grams/milliliters (g/mL) is its unit
- 1.8pm is measurement for length because length can be measured in picometer (pm).
- 250m2 is measurement for area because metre² (m²) is its unit.
- 325K is measurement for temperature because Kelvin is the absolute unit for temperature.
- 5.4mL is measurement for volume because volume can be measured in milliliters (ml).
- 90kg is measurement for Mass because kilograms (s) is its unit.
How would an increased level of acetyl-CoA be expected to affect the pyruvate dehydrogenase reaction
Answer:
The pyruvate dehydrogenase kinase enzyme activity would increase, resulting in an inhibition of pyruvate dehydrogenase activity. ... An in vitro study shows that isocitrate dehydrogenase is activated in the citrate cycle.
Explanation:
Can someone do a True or false for these
Answer:
all i can accurately say is that 2 and 4 are both true
Q2.
This question is about metals and metal compounds.
(a)
Copper oxide reacts with hydrochloric acid to produce copper chloride and water.
Copper oxide is insoluble in water.
Copper oxide is gradually added to hydrochloric acid until in excess.
Magnesium reacts with hydrochloric acid to produce magnesium chloride and hydrogen.
Plan an investigation to find the accurate volume of hydrogen produced from
magnesium
You do not need to write about safety precautions.
Answer:
sry I don't know the answer
please provide is matter about us pure all NCERT questions and answers
Answer:
I hope that's what u were lookong for :))
Explanation:
hey armies.. how are you doing
Answer:
Nice and you
Explanation:
Please Mark me brainliest
Calculate the average atomic mass for element X.
(Please HELP)
A gamma wave has____
energy than a radio wave.
A television wave has a
th
Answer:
more
Explanation:
seems like you did not finish the questions
The normal boiling point of ethanol is 78.4 oC. Its enthalpy of vaporization is 38.6 kJ/mol. Estimate the vapor pressure of ethanol at 26.3 oC.
Answer: The vapor pressure of ethanol at [tex]26.3^{o}C[/tex] is 238.3 torr.
Explanation:
Given: [tex]\Delta H_{vap}[/tex] = 38.6 kJ/mol
[tex]T_{1} = 26.3^{o}C = (26.3 + 273) K = 299.3 K[/tex]
[tex]T_{2} = 78.4^{o}C = (78.4 + 273) K = 351.4 K[/tex]
Formula used to calculate the vapor pressure of ethanol is as follows.
[tex]ln\frac{P_{2}}{P_{1}} = \frac{\Delta H_{vap}}{R} [\frac{1}{T_{1}} - \frac{1}{T_{2}}]\\[/tex]
Substitute the values into above formula as follows.
[tex]ln\frac{P_{2}}{P_{1}} = \frac{\Delta H_{vap}}{R} [\frac{1}{T_{1}} - \frac{1}{T_{2}}]\\ \\ln \frac{760 torr}{P_{1}} = \frac{38600 J}{8.314 J/mol K}[\frac{1}{299.3} - \frac{1}{351.4}]\\\frac{760}{P_{1}} = 3.18\\P_{1} = 238.3 torr[/tex]
Thus, we can conclude that the vapor pressure of ethanol at [tex]26.3^{o}C[/tex] is 238.3 torr.
Look at this balanced chemical reaction: N2 + 3H2 2NH3
How many grams of ammonia can be produced from reacting a 450 L sample of nitrogen gas at a temperature of 450 K and a pressure of 300 atm?
Answer: A mass of 124457.96 g ammonia is produced by reacting a 450 L sample of nitrogen gas at a temperature of 450 K and a pressure of 300 atm.
Explanation:
Given: Volume = 450 L
Temperature = 450 K
Pressure = 300 atm
Using ideal gas equation, moles of nitrogen are calculated as follows.
PV = nRT
where,
P = pressure
V = volume
n = no. of moles
R = gas constant = 0.0821 L atm/mol K
T = tempertaure
Substitute values into the above formula as follows.
[tex]PV = nRT\\300 atm \times 450 L = n \times 0.0821 L atm/mol K \times 450 K\\n = \frac{135000}{36.945}\\= 3654.08 mol[/tex]
According to the given equation, 1 mole of nitrogen forms 2 moles of ammonia. So, moles of ammonia formed by 3654.08 moles of nitrogen is as follows.
[tex]2 \times 3654.08 mol\\= 7308.16 mol[/tex]
As moles is the mass of substance divided by its molar mass. So, mass of ammonia (molar mass = 17.03 g/mol) is as follows.
[tex]Moles = \frac{mass}{molar mass}\\7308.16 = \frac{mass}{17.03 g/mol}\\mass = 124457.96 g[/tex]
Thus, we can conclude that a mass of 124457.96 g ammonia is produced by reacting a 450 L sample of nitrogen gas at a temperature of 450 K and a pressure of 300 atm.
 Help ASAP only right answers only no spam don’t answer if you don’t know
An atom has9 electrons and 9 protons at the start. If it loses 2 electrons, what would the net charge on the atom be
Answer:
i hope it will help you
Explanation:
there will be 7 electrons and 9 protons will have 2+ charge.
You burn a log on a fire. You use fire to warm yourself and help you see to read a book. What energy transformation is taking place?
Answer:
heat energy to keep you warm and light energy to be able to read your book
Explanation:
A new element R shows chemical properties similar to the element sodium. What is the correct formula of a compound formed with R and sulfur?
R₂S
RS₂
RS
R₂S₂
Answer:
R2S this is because sodium has one 1 valence and sulfur has valence of 2 so when they combine theyinterchange their valence