Answer:
C. keep the temperature constant so the collected gas will not expand
Explanation:
A water bath is an instrument in the laboratory used for controlled temperature experiment. It is used to maintain a constant temperature of volume of samples of water, air or chemicals. It consist of water being heated at a regulated and required temperature. Where the volume of the sample is placed in the water bath during an experiment so as to avoid unnecessary expansion of the sample.
In the question given, the purpose of putting the flask in a water bath during the experiment is to ensure that the content of the flask is at a constant temperature and avoid unnecessary expansion. Thus the correct option is C.
in which instrument of the following the washer works works as a valve? a)syringe b)hydraulic garage lift c)air pump d)watre pump
Answer:
A
Explanation:
The instrument in which the washer works as a valve is A ; syringe
Each instrument listed have a washer and a valve, but of all the instruments listed above the instrument that its washer works also as a valve is the syringe.
A syringe is composed of a thin tube and a thinner hollow needle attached to the end of the thin tube. the needle is used and take in liquids and also expel liquids from the syringe ( i.e. washer and valve )
hence the instrument that its washer also functions as a valve is the syringe.
learn more about syringe : https://brainly.com/question/24283167
A published hypothesis:
A: does not need to be tested
B: becomes a scientific law
C: should be tested by the scientific community
D: is accepted by the scientific community
Answer:
C
Explanation:
I hypothesis needs to be tested to know whether it is true or not. Here is the definition:
A supposition or proposed explanation made on the basis of *limited evidence as a started point for further investigation*
can u plz solve it n send the answer
1. Cl2 + H2O → HOCl + HCl
2. Tooth decay starts when when the pH of the mouth is lower than 5.5. Tooth enamel is made up of calcium phosphate and it is one of the hardest substances of the body. But it is corroded when the pH is less than 5.5. The bacteria of our mouth produce acids by degradation of sugar and food particles remaining in our mouth after eating food.
3. Fluorine salts are added in toothpaste to protect our teeth from tooth decay. Fluorine salts are mildly basic, so they neutrelise the acid in our mouth that leads to tooth decay.
4. Tincture of iodine is iodine, pottasium iodide and sodium iodide dissolved in ethanol. Iodine acts in an antiseptic manner by destroying microbial proteins and DNA.
5. Tincture of iodine is clear and reddish brown liquid.
how do i calculate the concentration of a certain solution
Answer:
Divide the mass of the solute by the total volume of the solution. Write out the equation C = m/V, where m is the mass of the solute and V is the total volume of the solution. Plug in the values you found for the mass and volume, and divide them to find the concentration of your solution.
What was the main aim of Cavendish’s work?
Answer:
The Cavendish experiment, performed in 1797–1798 by English scientist Henry Cavendish, was the first experiment to measure the force of gravity between masses in the laboratory and the first to yield accurate values for the gravitational constant
Explanation:
I think that's correct
Question 6 I need help
The answer is zero also I suggest googling the questions there is a quizlet with the answers
Which is the formula mass of (NH4)2SO4?
96.07 amu
114.12 amu
116.17 amu
132.17 amu
Answer:
132.17amu
Explanation:
(14.01+1.01 multiplied by 4)=18.05×2=36.1
36.1+32.07= 68.17
16.00×4=64
68.17+64=132.17
Answer:
132.17 amu
Explanation:
just took the test. got 100
how many Molecules and atoms of the product 2H2O+ O2
Answer:
A water molecule is composed of two hydrogen atom and one oxygen atom but you can't simply take two hydrogen atom stick them onto an oxygen atom
Analysis of an ore of calcium shows that it contains 13.61 g calcium and 21.77 g oxygen in a 46.28-g sample. Calculate the percent composition of this compound.
Answer:
29.41% of Calcium and 47.04% of Oxygen
Explanation:
The percent composition of an atom in a molecule is defined as 100 times the ratio between the mass of the atom and the mass of the molecule.
The mass of the molecule of the problem (Ore) is 46.28g. That means the percent composition of Calcium is:
13.61g / 46.28g * 100 = 29.41% of Calcium
And percent composition of Oxygen is:
21.77g / 46.28g * 100 = 47.04% of Oxygen
A gas at 100 Celsius has a volume of 33.5 L. What is its new volume after it is cooled to 25 Celsius?
Answer:
[tex]\boxed {\boxed {\sf 8.38 \ L}}[/tex]
Explanation:
We are asked to find the new volume of a gas after a change in temperature. We will use Charles's Law, which states the volume of a gas is directly proportional to the temperature. The formula for this law is:
[tex]\frac {V_1}{T_1}= \frac{V_2}{T_2}[/tex]
The gas starts at 100 degrees Celsius and a volume of 33.5 liters. Substitute these values into the formula.
[tex]\frac {33.5 \ L}{100 \textdegree C}=\frac{ V_2}{T_2}[/tex]
The gas is cooled to 25 degrees Celsius, but the volume is unknown.
[tex]\frac {33.5 \ L}{100 \textdegree C}=\frac{ V_2}{25 \textdegree C}[/tex]
We want to find the volume of the gas after it is cooled. We must isolate the variable V₂. It is being divided by 25 degrees Celsius and the inverse of division is multiplication. Multiply both sides of the equation by 25 °C.
[tex]25 \textdegree C*\frac {33.5 \ L}{100 \textdegree C}=\frac{ V_2}{25 \textdegree C}* 25 \textdegree C[/tex]
[tex]25 \textdegree C*\frac {33.5 \ L}{100 \textdegree C}= V_2[/tex]
The units of degrees Celsius cancel.
[tex]25*\frac {33.5 \ L}{100 }= V_2[/tex]
[tex]8.375 \ L = V_2[/tex]
The original measurements have 3 significant figures, so our answer must have the same. For the number we found, that is the hundredth place. The 5 in the thousandths place tells us to round the 7 up to an 8.
[tex]8.38 \ L \approx V_2[/tex]
The new volume after the gas is cooled is approximately 8.38 liters.
BJECTIVE TYPE QUESTIONS
Fill in the blank spaces by choosing the correct words from the words given in list.
List : composition, heat, chemical, photosynthesis, physical
1. Heating of zinc oxide is a
change.
2. Burning of coal is a
change.
3. There is a change in state and
during a chemical change.
4. Plants make their food by the process of
5.
energy is generally given out or absorbed during a chemical change
Answer:
1.Physical change
2. Chemical change
3. Heat
4.photosynthesis
5. composition
what does high pressure systems usually cause?
Arrange the following bonds in order of increasing ionic character:
C - H
F - H
Br - H
Na - Cl
K - F
Li - Cl
Answer:
This is the answer
C-H, Br-H, F-H, LI-CI, Na-CI, K-F
Hope this helps.
Consider the reaction. 2HF(g)—H2(g)+F2(g). What is the value of Keq for the reaction expressed in scientific notation
Answer:
A). 2.1 × [tex]10^{-2}[/tex]
Explanation:
Given reaction,
2[tex]HF[/tex] (g) ⇄ [tex]H_{2}[/tex] (g) + [tex]F_{2}[/tex] (g)
The concentrations are as following;
[tex]HF[/tex] = 5.82 × [tex]10^{-2}[/tex] M
[tex]H_{2}[/tex] = 8.4 × [tex]10^{-3}[/tex] M
[tex]F_{2}[/tex] = 8.4 × [tex]10^{-3}[/tex] M
So,
[tex]K_{eq}[/tex] = [([tex]H_{2}[/tex] ) × ([tex]F_{2}[/tex])] ÷ [[tex]HF[/tex]]^2
Now,
We can determine the value of [tex]K_{eq}[/tex] by substituting the values in above formula:
[tex]K_{eq}[/tex] = [ (8.4 × [tex]10^{-3}[/tex] M) × (8.4 × [tex]10^{-3}[/tex] M)] ÷ [(5.82 × [tex]10^{-2}[/tex])^2
= 2.08 * [tex]10^{-2}[/tex]
= 2.1 × [tex]10^{-2}[/tex]
∵ [tex]K_{eq}[/tex] = 2.1 × [tex]10^{-2}[/tex]
Thus, option A is the correct answer.
Values for the molar mass of hydrogen, oxygen, and water molecules are
given in the table below. What mass of water is formed when 2 moles of
hydrogen react with 1 mole of oxygen to form water?
Molecule
Molar mass (g/mol)
H2
2.02
02
32.00
H20
18.01
A.9.00 g
B. 36.02 g
C. 2.00 g
D. 18.01 g
Answer:
36.02g bbbbbbbbbbb hbbnjkkkj
Answer:
36.02g
Explanation:
Hope this helps!
Which condition will probably not increase
the rate of reaction?
a. Adding water to dilute the reaction
mixture
b. Increasing the temperature
c. Adding a catalyst
d. Removing an oxide coating on a
metal
Answer:
i think A.
Explanation:
bc B. makes the molecules hight temp = move faster = more collisions = higher rate, C. it's use is to make reactions rates increase, D. somthung abt more surface area and easier collisions
Compare the reactivity of Sodium and Potassium when reacting with Chlorine.
Explanation:
Both sodium and potassium belong to the same group. They both have only one electon in their outermost shell. But they belong to different periods. Sodium has 3 shells while potassium has 5. As the distance between the valence electron and the nucleus is more in potassium. It experience lesser pull by the nucleus and so can give away the valence electron very easily as compared to sodium which experience a greater pull from the nucleus. Thus potassium is more reactive. Reactivity increases on moving down the group.
Answer:
Sodium and potassium belongs to same group . Both has 1 electron to donate but sodium is less reactive because nuclear attraction makes it little bit difficult to loose electron as compared to potassium in which nuclear attraction becomes unable to pull the electrons towards itself . Hence we easily remove electron moreover due to screening effect also takes place .
Putting rock salt on the roads during a snowstorm is an example of: A. Boiling point elevation B. Vapor pressure raising C. Vapor pressure lowering D. Freezing point depression
Answer:
The correct answer is - D. Freezing point depression.
Explanation:
When rock salt is spread over snow-covered icy roads, it generates a liquid layer over it by melting from the surface thereby lowering or depression in the freezing point below the ice.
Therefore, due to this liquid layer comes into the contact with the ice present on the road and causes other ice to melts. This keeps on decreasing the volume of the ice on the road therefore, rock salts spread on the roads during a snowstorm.
How many moles of KClO3 must decompose in order to produce 9 moles of oxygen gas (O2) using the following reaction by completing the t-chart below.
Answer: 6 moles of [tex]KClO_3[/tex] will be decomposed.
Explanation:
We are given:
Moles of oxygen gas produced = 9 moles
The chemical equation for the decomposition of [tex]KClO_3[/tex] follows:
[tex]2KClO_3\rightarrow 2KCl+3O_2[/tex]
By the stoichiometry of the reaction:
If 3 moles of oxygen gas is produced by 2 moles of [tex]KClO_3[/tex]
So, 9 moles of oxygen gas will be produced by = [tex]\frac{2}{3}\times 9=6mol[/tex] of [tex]KClO_3[/tex]
Hence, 6 moles of [tex]KClO_3[/tex] will be decomposed.
Scientists in a lab are working on a series of experiments that involve colliding two or more atomic nuclei at very high speeds to form a new type of atomic nucleus. What are they working on?
convection
radiation
nuclear fusion
nuclear fission
Answer: Scientists are working on nuclear fusion process. Nuclear fusion is the process in which two atomic nuclei combine to form another nuclei. In the process either energy is absorbed or released due to the difference in the mass of reactants and products.
Explanation:
Imagine that you move a substance from one container to another and its volume changes.
What state of matter is that substance?
gas
solid
liquid
Answer:
Gas
Explanation:
If you move a substance from one container to another and its volume changes, the substance is a gas. This is because, gases do not have fixed volume and shape; their shape and volume depend on the container used.
Answer:
I think gas.
Explanation:
Because gas doesn't have fixed shape and size.
Some consumers, like lions, do not eat plants or any other producers. They only eat other animals. How do lions obtain the carbon they need?
whoever gets it first gets to be Brainlist
Answer:
BHAI SECOND OPTION HOGA
Answer:b
Explanation:
Name five metal which are both dilute and memorable? class 10
2. Nitric oxide contains 46.66% nitrogen and 53.34% oxygen. Water contains 11.21% hydrogen and 88.79% oxygen. Ammonia contains 17.78% hydroger and 82.22% nitrogen. Use these data to verify the law of reciprocal proportions.
Answer:
The law of reciprocal proportions states that if two elements react individually with a given weight of a third element, the ratio of the masses with which they combine with the third element are either the same or a simple multiple of the ratio of the masses with which they combine with each other
The compounds formed includes;
1) Nitric oxide, NO
Nitrogen = 46.66% × 30.01 = 14
Oxygen = 53.34% × 30.01 = 16
2) Water, H₂O
Hydrogen = 11.21% × 18.01528 = 2
Oxygen = 88.79% × 18.01528 ≈ 16
3) Ammonia, NH₃
Hydrogen = 17.78% × 17.031 ≈ 3
Nitrogen = 82.22% × 17.031 ≈ 14
The ratio of nitrogen to oxygen in nitric oxide = 14:16 = 7:8
The ratio of nitrogen to hydrogen in ammonia = 14:3
The ratio in which hydrogen and oxygen combine with nitrogen = 3/16
The ratio of hydrogen and oxygen combine with each other in water = 2/16
Therefore, the ratio with which hydrogen and oxygen combine with nitrogen, is (2/3) times the ratio with which they combine with each other, which verifies the law of reciprocal proportions
Explanation:
oil wells like the one shown here are used to obtain oil from which type of rock underground
Answer:
petroleum
Explanation:
usually found sedimentary rock.
definition: a liquid mixture of hydrocarbons that is present in certain rock strata and can be extracted and refined to produce fuels including gasoline, kerosene, and diesel oil, oil
Using dobereiner's triads, what conclusion could have been made about magnesium
Answer:
Triads were groups of 3 elements with similar chemical and physical properties. Beryllium, magnesium, and calcium are all earth alkalis found in the earth
Explanation:
A gas that was cooled to 200 Kelvin has a volume of 65.8 L. If its initial volume was 132.4 L, what was its initial temperature?
Answer:
Initial temperature, T1 = 99.4 Kelvin
Explanation:
Given the following data;
Initial volume, V1 = 65.8 LitresFinal temperature, T2 = 200 KelvinFinal volume, V2 = 132.4 LitresTo find the initial temperature (T1), we would use Charles' law;
Charles states that when the pressure of an ideal gas is kept constant, the volume of the gas is directly proportional to the absolute temperature of the gas.
Mathematically, Charles' law is given by the formula;
[tex] \frac {V}{T} = K [/tex]
[tex] \frac {V_{1}}{T_{1}} = \frac {V_{2}}{T_{2}} [/tex]
Making T1 as the subject formula, we have;
[tex] T_{1} = \frac {V_{1}T_{2}}{V_{2}} [/tex]
Substituting the values into the formula, we have;
[tex] T_{1} = \frac {65.8 * 200}{132.4} [/tex]
[tex] T_{1} = \frac {13160}{132.4} [/tex]
Initial temperature, T1 = 99.4 Kelvin
Please hurry!!!!!
this is due tomorrow morning
The periodic table is organized into groups and periods of elements. The characteristics of a certain group of elements are listed below.
Characteristics of a Group of Elements
• Is shiny
• Is solid at room temperature
• Has atoms with two valence electrons
Which of these elements is in this group?
F Lithium
G Strontium
H Aluminum
J Silicon
Answer:
Strontium is the elements which can be found in this group as it is shiny, is solid in room temperature and has atoms with two valence electrons.
Given: CNO2
a) Draw the Lewis structures (Do not forget to show the calculation of the number of available valance electrons)
b) Name the geometry shape
c) Indicate the polarity (polar or non-polar)
Answer:
since there are no lone pairs on the central atom, this would be a trigonal planar molecule. It's polar because the shape of it does not cancel its polarity (you can think of it as not having a balanced electronegativity pull, since the nitrogen is pulling on one side, and the oxygens are pulling on the other. It would be nonpolar if the there were 3 Oxygens).
Sorry this take a little bit long. I was a little confused by the odd valence number
Match each lab incident to the item of PPE that will protect you from it. Each item of PPE will only be used once.
While picking up a buret, an unknown solution left by a previous solution drips onto your hand._______________
While pulling an empty beaker off the shelf at the beginning of lab, it slips out of your hand onto the floor _______
While checking on a stirring solution, the solution splashes up towards your face. _______
While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench, __________
A. Gloves
B. Lab coat
C. Goggles
D. Closed-toe shoes
While picking up a buret, an unknown solution left by a previous solution drips onto your hand - Gloves
While pulling an empty beaker off the shelf at the beginning of lab, it slips out of your hand onto the floor - Closed-toe shoes
While checking on a stirring solution, the solution splashes up towards your face - Goggles
While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench - Lab coat
Explanation:
The full form of PPE is 'Personal Protective Equipment'.The PPE items we use in labs are : Lab coat: Protection of clothing and skin from accidental spilling of hot liquid or toxic substances. Gloves: Protection from hands from chemicals, hot objects, sharp tools, or electricityGoggles: Protection of the eye from any chemicals, toxic vapor, chemical debrisFace shield: Protection of the face from any chemicals, toxic vapor, chemical debrisClosed-toe shoes: Protection from feet from chemicals, hot objects, sharp tools, or electricitySo, according to the question. the matches will be:
While picking up a buret, an unknown solution left by a previous solution drips onto your hand - Gloves
While pulling an empty beaker off the shelf at the beginning of lab, it slips out of your hand onto the floor - Closed-toe shoes
While checking on a stirring solution, the solution splashes up towards your face - Goggles
While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench - Lab coat
Learn more about PPE here:
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