Which of the following statements is true regarding scientific hypotheses?
A.Every hypothesis is valuable, whether or not it is testable.
B.A testable hypothesis is valuable, even if evidence shows that it is false.
C. A testable hypothesis is valuable only if all evidence supports it. D. There are no valuable hypotheses.
1
Complete and balance the following equations : Al + NaOH +___--->_____+____
Answer:
Al + 3NaOH = Al(OH)₃ +3Na
Explanation:
The reaction is given as:
Al + NaOH = Al(OH)₃ + Na
This reaction is called a single displacement reaction in which one specie displaces another from a solution.
To balance the equation:
aAl + bNaOH = cAl(OH)₃ + dNa
a, b, c and d are the coefficient that will balance the equation:
Conserving Al;
a = c
Conserving Na;
b = d
Conserving O;
b = 3c
Conserving H;
b = 3c
Let a = 1, c = 1, b = 3 and d = 3
Al + 3NaOH = Al(OH)₃ +3Na
How many moles are in 16.2 grams of lithium ?
Answer:
6.941 moles
Explanation:
Why is Bohr diagram better than orbital diagram ?
Answer:
hfjdjdjdjdjdjdjd
Explanation:
rjeiejejejeje
Determine whether each statement is an example of a physical change or a chemical change. Paper is shredded. physical chemical
Answer:
That would be a physical change
Explanation:
A physical change is when you are changing the physical properties of something but not changing its overall identity and a chemical change is when yo are changing the physical properties and changing its identity .
Ex. Ripping a dollar bill- Physical change
Burning a dollar bill- chemical change
Answer:
first one is physical , second one is chemical
Explanation:
Nitrogen changes from a liquid to a gas at the same temperature at
which water changes from a liquid to a gas.
True or false
Answer:
False
Explanation:
if this were true then water would not be available on earth other than in the atmosphere because of evaporation
(Gr.7science)
Can somebody plz help answer both these questions only in 1-2 sentences if u can thanks! :D
WILL MARK BRAINLIEST..promise
Answer:Crystalline solids have well-defined edges and faces, diffract x-rays, and tend to have sharp melting points. In contrast, amorphous solids have irregular or curved surfaces, do not give well-resolved x-ray diffraction patterns, and melt over a wide range of temperatures.
Explanation:
Answer:
:-::-::
Explanation:
Para un sistema, el valor de la constante que resulta del cociente entre el producto de la presión y el volumen con la temperatura es de 0,03 (atmxL/K). ¿cuál debe ser el valor de la temperatura del sistema para el volumen y la presión tengan valores 4500mL y 4,5atm?
Answer:
675 K
Explanation:
[tex]\dfrac{P_1V_1}{T_1}=0.03\ \text{atm L/K}[/tex]
Presión del sistema 2 = [tex]P_2=4.5\ \text{atm}[/tex]
Volumen del sistema 2 = [tex]V_2=4500\ \text{mL}=4.5\ \text{L}[/tex]
De la ley de los gases ideales tenemos la relación
[tex]\dfrac{P_1V_1}{T_1}=\dfrac{P_2V_2}{T_2}\\\Rightarrow 0.03=\dfrac{4.5\times 4.5}{T_2}\\\Rightarrow T_2=\dfrac{4.5\times 4.5}{0.03}\\\Rightarrow T_2=675\ \text{K}[/tex]
La temperatura del sistema para el segundo sistema es 675 K.
Identify the correctly written chemical reaction.
A. Reactant + Product → Reactant + Product
B. Product + Product → Reactant + Reactant
C. Reactant + Reactant = Product
O
D. Reactant + Reactant → Product + Product
Answer:
eek um A.The substance(s) to the left of the arrow in a chemical equation are called reactants. The substance(s) to the right of the arrow is called products.
Explanation:
How does the amount of baking soda used affect the size of the cookie baked?
Calculate the pH of 0.02 M methanoic acid where Ka = 1.6 x 10^-4 M.
Answer:
pH = 2.75
Explanation:
Methanoic acid, HCOOH, is in acidic equilibrium:
HCOOH ⇄ HCOO⁻ + H⁺
And Ka is defined as:
Ka = 1.6x10⁻⁴ = [HCOO⁻] [H⁺] / [HCOOH]
As both HCOO⁻ and H⁺ ions comes from the same equilibrium, we can solve these concentrations assuming the HCOOH produce X of both HCOO⁻ and H⁺ ions:
1.6x10⁻⁴ = [HCOO⁻] [H⁺] / [HCOOH]
1.6x10⁻⁴ = [X] [X] / [0.02M]
3.2x10⁻⁶ = X²
X = 1.79x10⁻³M = [H⁺]
As pH = -log [H⁺]
pH = 2.75The pH of the 0.02 M methanoic acid is 2.75 acid when the dissociation constant is [tex]1.6 \times 10^{-4} \rm \ M.[/tex]
At equilibrium, the dissociation of Methanoic acid,
HCOOH ⇄ HCOO⁻ + H⁺
In the reaction, Methanoic acid dissociates to form HCOO⁻ and H⁺. So, the concentration of both products will be equal.
pH can be calculated by using Ka,
[tex]\bold{Ka = \dfrac {[HCOO^-] [H^+] }{[HCOOH]}}[/tex]
Where,
Ka - dissociation constant = 1.6x10⁻⁴
[HCOOH ] - concentration of Methanoic acid = 0.02 M
[tex]\bold{1.6 \times 10^{-4} M.= \dfrac {[HCOO^-] [H^+] }{[HCOOH]}}[/tex]
Let the concentration of each product is [tex]x[/tex]
So,
[tex]\bold{1.6 \times 10^{-4} \ M}= \dfrac {[x] [x] }{[0.02]}}\\x^2 = 3.2\times 10^{-6}\\x = 1.79\times 10^{-3}\rm \ M[/tex]
Put the value in the pH formula,
[tex]\bold {pH = - log [H^+]}\\\\\bold {pH =- log \ 1.79\times 10^{-3}\rm \ M}\\\\\bold {pH = 2.75 }[/tex]
Therefore, The pH of the 0.02 M methanoic acid is 2.75 acid when the dissociation constant is [tex]1.6 \times 10^{-4} \rm \ M.[/tex]
Learn more about dissociation constant:
https://brainly.com/question/7145687
What decision did George make?
never to have fun again
never to be so irresponsible again
never to go boating again
Answer:
(2) never to be so irresponsible again
Explanation: hope this help!
Answer:
never to be so irresponsible again. is it right.
Is it possible for something such as a cake or a potato to get so hot that it melts? Normally when you heat something up a whole lot, it melts, but when you put liquid cake batter in an oven it turns into a solid, then it burns, but is there a way to heat it up so much so that it turns back into a liquid? Same thing with a potato, if you heat it up, it will burn, but can you turn a potato into a liquid by heating it up too much? Plz help im rlly stuck...
Answer:
I dont think so. If you continue to heat them up they will shrink and dissapper r become ashes. Thats a very interesting question btw. :) hope this helps!
Explanation:
Which of the following are properties of ionic compounds?
A. hard solids with high melting and boiling points.
B. soft and good conductors of electricity.
C. both A and B
D. good conductors of electricity, but only when dissolved in water
Answer:a and d
Explanation:
The properties of ionic compounds are hard solids with high melting and boiling points and good conductors of electricity, but only when dissolved in water and the correct options are option A and D.
What are Ionic solids?Ionic solids are made up of ions joined together by ionic bonds. "Ionic bonding" is a type of chemical bond between a positive and a negatively charged ion where the transfer of electrons occurs.
They are too hard, and the ionic solids’ melting point is usually too high due to powerful forces between the anions and cations.
They are known as electrical insulators when they are in a solid-state. Apart from this, the molten salts do behave with electricity since the ions are not closed in the lattice.
Therefore, the properties of ionic compounds are hard solids with high melting and boiling points and good conductors of electricity, but only when dissolved in water and the correct options are option A and D.
Learn more about Ionic solids, here:
https://brainly.com/question/15241125
#SPJ2
How much heat is needed to raise a 0.060 kg piece of granite from 82°C to 212 °C.
(The specific heat capacity of granite is 0.790
Answer:
There are required 6162J to raise the temperature of the piece of granite from 82°C to 212°C
Explanation:
By using the equation:
Q = m×C×ΔT
Where Q is heat in J, our incognite
m is mass of the substance, 0.0600kg = 60.0g
C is specific heat, 0.790J/g°C
And ΔT is change in temperature, 212°C - 82°C = 130°C
Replacing:
Q = m×C×ΔT
Q = 60.0g×0.790J/g°C×130°C
Q = 6162J
There are required 6162J to raise the temperature of the piece of granite from 82°C to 212°C
A substance is called malleable
Answer: Malleability is a substance's ability to deform under pressure (compressive stress). If malleable, a material may be flattened into thin sheets by hammering or rolling. Malleable materials can be flattened into metal leaf. Examples of malleable metals are gold, iron, aluminum, copper, silver, and lead.
Explanation: This what you needed?
Answer:
Malleability is a substance's ability to deform under pressure (compressive stress). Examples of malleable metals are gold, iron, aluminum, copper, silver, and lead. Gold and silver are highly malleable. When a piece of hot iron is hammered it takes the shape of a sheet.
HELP I NEED HELP ASAPP
Answer:
B = A/DH – C
Explanation:
From the question given above, we obtained:
A = D • H(B + C)
Thus, we can obtain B in terms of D, H, A and C by doing the following:
A = D • H(B + C)
A = DH(B + C)
Divide both side by DH
A/DH = B + C
Subtract C from both side
A/DH – C = B + C – C
A/DH – C = B
B = A/DH – C
GIVING BRAINLEST TO WHOEVER HAS THE RIGHT ANSWER!! ANSWER QUICK PLZ. Plz and Tysm
If I want to increase the
potential energy of a tennis ball that I am holding I would________
1. hold it closer to the ground
2.Hold it further from the ground
3.drop it
4.bounce it
Answer:
2. Hold it further from the ground
Explanation:
If I want to increase the potential energy of the tennis ball I am holding, it is best advised to hold the ball further from the ground.
Potential energy is the energy at rest in a body. It is dependent on the mass, gravity and height of body.
Potential energy = mass x gravity x height
Height is directly proportional to potential energy.
Find the mass of 22.7 liters of CH4 gas at 200.0 kPa and 50.0°C.
Answer:
Mass = 27.2 g
Explanation:
Given data:
Volume of gas = 22.7 L
Pressure of gas = 200.0 KPa (200/101=1.97 atm)
Temperature = 50.0°C
Mass of gas = ?
Solution:
The given problem will be solve by using general gas equation,
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
Now we will convert the temperature.
50+273 = 323K
1.97 atm ×22.7 L = n × 0.0821 atm.L/ mol.K × 323K
44.72 atm.L = n × 26.52 atm.L/ mol
n = 44.72 atm.L / 26.52 atm.L/ mol
n = 1.7 mol
Mass of CH₄:
Mass = number of moles × molar mass
Mass = 1.7 mol × 16 g/mol
Mass = 27.2 g
Bridget performed an investigation to determine if a television set transformed electrical energy into other types of energy. She recorded her observations in a table.
What statement best describes the results?
Question Observation
Does it transform into heat energy? Yes
Does it transform into light energy? Yes
Does it transform into sound energy? Yes
Does it transform into energy of motion? No
1 A television transforms electrical energy into heat and light energy.
2 Electrical energy transforms into more than one type of energy.
3 Sound energy is transformed from heat and light energy.
4 You can transform electrical energy into energy of motion.
all my points if u answer themmm
Answer:
2 ;)
Explanation:
Which substances will make a salt when combined?
Answer:
Sodium and chlorine combine to make salt
Explanation:
Answer:
vinegar and soda
Explanation:
:)
For what is the Endocrine system responsible for?
I will report your answer If its just to get points
A: Breathing.
B: Maintaining Homostasis.
C: Ridding of waste.
D: Protecting from Invaders.
Answer:
B: Maintaining Homostasis
Explanation:
Think of ways that carbon atoms can enter our bodies. List as many possibilities as you can.
Answer:
Explanation:
The element CARBON enters the body in two NATURAL ways.
First is through eating and drinking. Almost all food that we eat contain the element carbon. As the ingested food reaches the digestive system, food is broken down into smaller pieces up until the molecular level. Some molecules are taken into the circulation, while others are excreted down as feces.
Second is by breathing. Certain air molecules contain carbon. One major air molecule is CARBON DIOXIDE. Some molecules are inhaled, but usually, CARBON DIOXIDE should be excreted from the body.
Unnatural ways when CARBON could enter the body is by medical intervention, as in intravenous injections, surgery, etc
6. The modern view of the atom has come a long way from that of a solid, indestructible sphere
O True
O False
Instructions: complete and balance the chemical equations for each chemical reaction in the virtual lab activity.
1. Combine iron and copper (II) sulfate solution. (Hint: Iron will form the iron (III) ion)
Fe + CuSO4 →
2. Combine lead (II) nitrate and potassium iodide solutions.
Pb(NO3)2+ Kl →
3. Combine magnesium metal and hydrochloric acid solution.
Mg + HCl →
4. Electrolysis (splitting) of water.
H2O →
5. Burning magnesium.
Mg + O2 →
Answer:
1. Combine iron and copper (II) sulfate solution. (Hint: Iron will form the iron (III) ion)
Fe + CuSO4 → FeSO4 + Cu
2. Combine lead (II) nitrate and potassium iodide solutions.
Pb(NO3)2+ Kl → Pbl2 + 2KNO3
3. Combine magnesium metal and hydrochloric acid solution.
Mg + HCl → MgCl2 + H2
4. Electrolysis (splitting) of water.
H2O → 2H2 + O2
5. Burning magnesium.
Mg + O2 → Mg2+O2-
Explanation:
Identify the labeled structures.
A:
B:
C:
D:
E:
cell membrane
Golgi body
mitochondrion
nucleus
vacuole
Explanation:
A = Golgi body
B = Vacuole
C = Mitochondrion
D = Nucleus
E = Cell membrane
Answer:
A = Golgi body
B = Vacuole
C = Mitochondrion
D = Nucleus
E = Cell membrane
Explanation:
give credit to the other person they helped me
too have a good day :)
How many grams are in 9.30 x 10-2 moles of calcium phosphate, Caz(PO3)2?
a. 25.9 g b. 17.65 g
c. 0.064 g
d. 259 g
Answer:
25.9 g
Explanation:
Given that,
No of moles of calcium phosphate, [tex]n=9.3\times 10^{-2}[/tex]
We need to find how many grams of calcium phosphate has this much of no of moles.
Mass divided by molar mass is equal to the no of moles on a molecule.
The molar mass of calcium phosphate is 310.18 g/mol
Using the concept of no of moles as follows :
[tex]n=\dfrac{m}{M}\\\\m=n\times M\\\\m=9.3\times 10^{-2}\times 310.18\\\\m=28.84\ g[/tex]
Out of given options, option (a) i.e. 25.9 g is the correct answer.
Which formula shows the proper use of parentheses?
Ca(F)2
Ca(SO)
O (NH4)3 (PO4)
Ca(NO3)2
Answer:
This one here shows the proper use of parentheses>>>Ca(NO3)2
What might happen if you mixed a strong acid with an equally strong base?
Question 4 options:
You would wind up with a pH neutral salt and water
The base would destroy the acid.
You would see an explosive chemical reaction.
The acid would destroy the base.
Answer:
You would wind up with a pH neutral salt and water
Explanation:
When they are equally strong they will both neutralize each other, and the acidic and basic properties are no longer there.
what does c3h8 equal