Answers
19. place moth balls in the closet and observe after several days.
20. whenever wax or a candle burns it turns from solid to liquid but again at room temperature it turns to solid
21. evaporation, condensation, precipitation
22. it produces new substances
23. vinegar Bubbles when baking soda is added
24. steam
Related Questions
explain with example the need of standard measurement system
Answers
Answer:
A standard system of measurement is very important because it helps us from making mistakes at the moment of doing calculations and correctly working...
Answer:
A standard measurement system is important because it allows scientists to compare data and communicate with each other about their results. Metric System – is a measurement system based on the number 10.
what is 10x412x3021x13123
Answers
The reaction from NaOH and CH3COOH gives
a. Basic Salt
b. Acidic Salt
c. Normal Salt
d. Neutral Salt
Answers
HELP ASAP!! PLZ
What information is needed to determine a molecular formula?
A. The empirical formula and the molarity of the solution
B. The empirical formula and the empirical formula mass
C. The empirical formula and the percent composition
ОО
D. The empirical formula and the molar mass
SUBMIT
Answers
D. The empirical formula and the molar mass
Freé point
[tex] \: \: \: \: \: \: [/tex]
Answers
Answer
Tq so much.
Pls follow me and Mark as brainliest Plsssssssss
Answer:
Thank you so much.
If an equilibrium system contains gaseous reactants and/or products, a change in volume will cause a change in concentration and pressure. A decrease in volume will cause the system to shift in the direction that produces _____ moles of gas in total, whereas an increase in volume causes a shift in the direction that produces _____ moles of gas in total.
Answers
Answer:
Less
More
Explanation:
When a constraint is imposed on a reaction system in equilibrium, the equilibrium position will shift in such a way as to annul the constraint.
When the volume of a reaction system in equilibrium is decreased, the equilibrium position will shift in the direction having less total number of moles.
Similarly, when the volume is increased, the equilibrium position shifts to the direction having a greater total number of moles.
what is the wave speed
a wave with a wave length of 1000 m and a frequancy of 3000000 Hz
Answers
Answer:
v = 3,000,000,000 m/s
Explanation:
v = f *L
v = 3,000,000 * 1000
v = 3,000,000,000 m/s
1. How many ATOMS of boron are present in 2.20 moles of boron trifluoride ? atoms of boron.
2. How many MOLES of fluorine are present in 5.35*1022 molecules of boron trifluoride ? moles of fluorine.
Answers
Answer:
1. How many ATOMS of boron are present in 2.20 moles of boron trifluoride? atoms of boron.
2. How many MOLES of fluorine are present in of boron trifluoride? moles of fluorine.
Explanation:
The molecular formula of boron trifluoride is [tex]BF_3[/tex].
So, one mole of boron trifluoride has one mole of boron atoms.
1. The number of boron atoms in 2.20 moles of boron trifluoride is 2.20 moles.
The number of atoms in 2.20 moles of boron is:
One mole of boron has ---- [tex]6.023x10^2^3[/tex] atoms.
Then, 2.20 moles of boron has
-[tex]=2.20 mol. x 6.023 x 10^2^3 atoms /1 mol\\=13.25x10^2^3 atoms[/tex]
2. Calculate the number of moles of BF3 in 5.35*1022 molecules.
[tex](5.35x10^2^2 molecules/6.023x10^2^3)x 1mol\\=0.0888mol[/tex]
One mole of boron trifluoride has three moles of fluorine atoms.
Hence, 0.0888moles of BF3 has 3x0.0888mol of fluorine atoms.
=0.266mol of fluorine atoms.
explain why the boiling point of aluminum is higher than sodium
Answers
Explanation:
this is the reason why aluminium's boiling point is higher than that of sodium. sodium forms Na+ ions, therefore 1 electron is lost from each sodium atom, whereas aluminium forms Al3+ ions, so 3 electrons are lost for each Aluminum atom. The number of delocalised electrons therefore increases from sodium to aluminium, and charge density of the ions increases as the ionic charge increases and size decreases.
10:38 Fri 9 Jul
ES
GCSE Science - Chemistry
2 of 15
Name the indicator that is red in acid and turns green when the solution becomes neutral.
|
Answers
Answer.
Universal indicator
Explanation.
Universal indicator has many different colour changes, from red for strongly acidic solutions to dark purple for strongly alkaline solutions. In the middle, neutral pH 7 is indicated by green.
The molar mass of oxygen(O) is 32g. What is the mass of 1.05*10^25 molecules of O²
Answers
Answer:
Hope that will help you
Explanation:
Text me for more answers
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.
Answers
Answer:
sry I don't know the answer
Which of the following equalities is not correct?
a. 1 cm^3 = 1 mL
b. 1000 mm = 1 m
c. 100 cg = 1 g
d. 10 kg = 1 g
Answers
Answer:
a. 1 cm^3 = 1 mL
explanation:
7. Explain the difference between an ionic compound and a molecule, on an atomic
level (that is, describe what is happening with the atoms that makes these compounds
different)
Answers
Answer:
bakit Kay's lahat Ng module mahirap
In an atomic model that includes a nucleus, positive charge is
a
concentrated at multiple sites in an atom.
b
concentrated in the center of an atom.
c
spread evenly throughout an atom.
d
located in the space outside the nucleus.
Answers
Which option best describes the water cycle?
Answers
A solution of known concentration is called
Answers
Answer:
It is called standard solution.
Explanation:
I hope this helps! Have a nice dayy! :)
Using the following samples below, elaborate on the practical uses of concave and convex
mirrors. Write your answer on a separate sheet of paper.
1. Car rear view mirror
2. Security
3. Street light reflectors
4. Shaving facial hair
5. Car light
Answers
Answer: Convex mirror is curved in the outward direction and concave mirror in the inward direction.
Explanation:
1. Car rear view mirror: It is a convex mirror which gives the indication of large field of view and it allows the driver to view the traffic behind the car.
2. Security: The reflective bulge surfaces of the convex mirrors reflect the light outwards and provides an expanded field of view of the entire view of shops and other places useful for security.
3. Street light reflectors: They use convex mirrors because they are able to spread the light over the wider area.
4. Shaving facial hair: Concave mirror is used in shaving facial hair. It gives a bigger view of face when it is at the position of pole and focal point of the mirror.
5. Car light: It uses concave mirror because of the converging power it can focus more light rays at a particular point.
what would happen if you boil a substance in an alcohol
Answers
Answer:
When a mixture of water and alcohol boils, the vapors are a mixture of water vapor and alcohol vapor
What is the wavelength of a wave that has a frequency of 6.1 x 109 Hz ? c = λυ where c = 2.998 x 108 m/s
a. 20.4 m
b. 2.04 m
c. 0.49 m
d. 0.049 m
Answers
Answer:
Wavelength = 0.049 m
Explanation:
Given that,
The frequency of a wave,[tex]f=6.1\times 10^9\ Hz[/tex]
We need to find the wavelength of the wave. We know that,
[tex]c=f\lambda\\\\\lambda=\dfrac{c}{f}\\\\\lambda=\dfrac{2.998 \times 10^8}{6.1\times 10^9}\\\\\lambda=0.049\ m[/tex]
So, the wavelength of the wave is 0.049 m.
For a reaction, AH = 176 kJ/mol and A SO = 0.285 kJ/(K•mol). At what
temperatures is this reaction spontaneous?
A. At no temperature
B. T< 50 K
C. T> 617 K
D. T< 617K
Answers
what kind of food preserve for curing
Answers
Answer:
bitter leaf soups
Explanation:
because it cures gems out our body system
Determine the enthalpy for the reaction A+B --> C If we know the following:
A+E --> C+D; delta H = -200 kJ
D+B --> E; delta H = -100 kJ
Answers
Explanation:
here is the answer to the question
Balance equation for. _Mg + _H3(PO4) --_Mg3(PO4)2+ _H2
Answers
I think
Why does every chemical reaction require a certain amount of activation energy?
Answers
Explanation:
Activation energy is the minimum amount of energy required for a chemical reaction to take place.
When a chemical reaction occurs then bonds between the reactants break and bonds between the products are formed. This leads to the formation of an activated complex which is also known as transition state.
So, in order to form the activated complex a minimum amount of energy is necessary and this energy is known as activation energy.
CH4 (g) + O2 (g) → CO2 (g) + H2O (g) to. If 28.6 g of CH4 is reacted with 57.6 g of O2, calculate the number of grams of CO2 produced. b. If you actually get 32.1 g of CO2, calculate the percent yield. c. Calculate the number of moles of excess reagent remaining at the end of the reaction.
Answers
Answer:
See explanation
Explanation:
First we must obtain the limiting reactant. The equation of the reaction is;
CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (g)
Number of moles of CH4= 28.6 g/16g/mol = 1.8 moles
Since the reaction is 1:1, 1.8 moles of CO2 was produced
Number of moles of O2 = 57.6 g/32 g/mol = 1.8 moles
2 moles of O2 produced 1 mole of CO2
1.8 moles of O2 produced 1.8 × 1/2 = 0.9 moles of CO2
Hence O2 is the limiting reactant
Mass of CO2 produced = 0.9 moles × 44 g/mol = 39.6 g
%yield = 32.1g/39.6 g × 100
%yield = 81.1%
According to the reaction equation;
2moles of O2 reacts with 1 mole of CH4
1.8 moles of O2 reacts with 1.8 × 1/2 =0.9 moles of CH4
Number of moles of CH4 left = 1.8 moles - 0.9 moles
Number of moles of CH4 left = 0.9 moles
alculating Displacement under Constant Acceleration
Use the information from the graph to answer the
question
What is the total displacement of the object?
m
Velocity vs. Time
40
30
Velocity (m/s)
20
10
0
0
5
10
15
20
25
Time (s)
Intro
Done
ODO
ODDO
tivity
Answers
Answer:
[tex]10 {7}^{2} = [/tex]
When a gas is heated,
Answers
Answer: when gas is heated ,they gain more kinetic energy causing them to move faster.
Explanation: so as they gain kinetic energy they hit the walls of the container with more force thus causing pressure to increase
HOPE THIS HELPSS comment if u need more explanation
How many ATOMS of boron are present in 3.61 grams of boron trifluoride ?
Answers
Answer:
To determine the number of atoms of Boron that are present within 3.61 grams of Boron Trifluoride, it would be best to convert the grams to moles of the compound and then after that use the Avogadro's number to determine the number of molecules and then use the 1 to 3 ratio to determine the total number of Boron atoms.
What is the symbol for an ion with a 3+ charge, 28 electrons, and a mass number of 71
Answers
Answer:
Ga3+ is a gallium cation
