why must a ph meter be calibrated by using a solution with a known ph value
Answer:
A pH calibration is the process of adjusting your pH meter by measuring solutions of a known pH value. This is because the characteristics of your electrode will change over time and this needs to be compensated for. A calibration does this by matching your pH meter to the current characteristics of your pH sensor.
Explanation:
mass is the gravitational pull on the earth
-tru
-fals
plz help
Answer:
I believe the answer is false
Explanation:
Earth's gravity comes from all of its mass. All the mass makes a combined gravitational pull on all the mass in an object. If you were on a planet with less mass than Earth, you would weigh less than you do here. Mass is the quantity of matter in a physical body. It is also a measure of the body's inertia, the resistance to acceleration when a net force is applied. An object's mass also determines the strength of its gravitational attraction to other bodies. Mass is not the gravitational pull on the earth.
Help me ASPAPPPPPPPPP
Answer:
Explanation:
1. H2O
Lewis Dot:
See the attachment.
Note the б+ and б- signs on the H and O atoms, respectively. Those represent the slightly positive and slightly negative sides of the water molecule. Those slight charges on a single water molecule are attracted to their opposite charges on neighboring H2O molecules, as shown in the graphic. This interaction is what gives water it's cohesive properties.
3. The property of cohesion describes the ability of water molecules to be attracted to other water molecules. which allows water to be a "sticky" liquid.
The hydrogen bonds are attractions of electrostatic force. They arise due to the difference in charge between the slightly positive hydrogen ion and the slightly negative oxygen ion. Hydrogen bonds form between neighboring hydrogen and oxygen atoms of adjacent water molecules. The attraction between individual water molecules creates a bond known as a hydrogen bond, and it is what gives water it's cohesiveness, or ability to support water spiders, paper clips, and produces a loud noise in the event of a belly flop in a pool (including the yelp from the swimmer).
4. I'm not sure what is being asked for the two blanks. Water is polar and dissolves salts (ionic compounds) and hydrophilic molecules (water-loving molecules).
The speed at which a chemical reaction proceeds is called
Answer:
Answer: Reaction Rate
Explanation:
reaction rate, in chemistry, the speed at which a chemical reaction proceeds. It is often expressed in terms of either the concentration (amount per unit volume) of a product that is formed in a unit of time or the concentration of a reactant that is consumed in a unit of time.
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What products are obtained by the electrolysis of CuSO4 solution using copper electrode ? Show with help of chemical reaction.
Answer: The products will be copper and oxygen.
Explanation: Copper electorde is an active electrode so it constantly takes part in the electrolysis. Cathode is a pure copper negative electrode and anode is a impure copper positive electrode. So the copper present in the solution, along with the copper present in the anode will come off and go to the cathode. As a result, cathode gains copper. And the remaining impurities settle down in the bottom.
In the anode, oxygen will be given off because according to the order of discharge, if SO4 is present then the ions will stay in the solution and oxygen will be released. So at the end, solution of SO4 and H2O will be remaining while copper and oxygen is extracted.
The half equations are-
Cathode: Cu2+ + 2e- = Cu
Anode: Cu + 2e- = Cu2+
Something you might not know: The solution in electrolysis turns blue when copper goes to the cathode. So copper electrodes are also used in electroplating.
Calcolate resulant force 15N <-[]->20N
Explanation:
5N right because -15N for left plus +20N for right = +5N
How many atoms are in 2 moles of oxygen?
Answer:
6.02 × 1,023
Explanation:
One mole of oxygen gas, which has the formula O2, has a mass of 32 g and contains 6.02 X 1,023 molecules of oxygen but 12.04 X 1,023 (2 X 6.02 X 1,023) atoms, because each molecule of oxygen contains two oxygen atoms.
I need help with stoichiometry
Which of the following methods of heat transfer causes the tectonic plates to move?
Conduction
Convection
Evaporation
Radiation
calculate the mass of sodium sample that it contains 2 Na atoms of sodium
please i need help with this ques.
Answer:
45.98 I believe if its wrong im sorry
The very act of you observing something
will disturb the system is known as:
Answer:
The observer effect is the answer.
How many moles of nitrogen dioxide, NO2, are present if the reaction conditions are 330 K, 2.46 atm, and 4.8 L
There are 0.436 moles of nitrogen dioxide, NO2, present if the reaction conditions are 330 K, 2.46 atm, and 4.8 L.
IDEAL GAS LAW:The number of moles of nitrogen dioxide (NO2) in this question can be calculated by using the ideal gas law equation as follows:
PV = nRT
Where;
P = pressure (atm)V = volume (L)T = temperature (K)R = gas law constant (0.0821 Latm/molK)n = number of molesAccording to the reaction conditions given in this question;
P = 2.46 atmV = 4.8Ln = ?T = 330K2.46 × 4.8 = n × 0.0821 × 330
11.81 = 27.093n
n = 11.81 ÷ 27.093
n = 0.436mol
Therefore, there are 0.436 moles of nitrogen dioxide, NO2, present if the reaction conditions are 330 K, 2.46 atm, and 4.8 L.
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RNA is a double strand. True or False?
Answer:
False, RNA is single stranded, DNA is double stranded and forms a double helix
Explanation:
4. When a turbine spins, it generates electrical energy and that is where it gets its name from.
How does a paper bag wrapped around a hot water bottle create convection?
Write the chemical formulas and names for the following ionic compounds. Barium and phosphate 
Barium is Ba. Atomic no. 56 and atomic mass =137.3.
Phosphate is naturally occurring form of phosphorus. Phosphate is P. Atomin no. 15 and atomic mass =31.0.
Don’t understand this science Question.
Answer:
I got you..you need help but with which question?
Explanation:
Have a great day!
what is the number of protons in a neutral atom with 31 electrons and 38 neutrons?
31
I think. Protons and electrons share the same number as well as the atomic number.
Answer:
31 protons
Explanation:
Protons are positively charged and electrons are negatively charged so if it is a neutrally charged atom (which most are) the protons and electrons will be equal.
How many grams of potassium sulphate are formed when 49g of sulphuric acid in solution are neutralised by potassium hydroxide?
Do the ingredients changing into a cake in the oven a chemical reaction?
Answer:
When you bake a cake, the ingredients go through a chemical change. A chemical change occurs when the molecules that compose two or more substances are rearranged to form a new substance! When you start baking, you have a mixture of ingredients. The flour, egg, sugar,
Explanation:
How is a chemical equation different from mathematical equation?
Only chemical equation uses + sign
Only chemical equation uses arrow instead of = sign
Only chemical equation has numbers
Only chemical equation has minuses
Answer:
Only chemical equation uses arrow instead of = sign
Answer:
Only chemical equation uses an arrow instead of a = sign.
A chemical equation depicts a chemical reaction by utilising chemical formulae and symbols to depict the reactants, products, and chemical changes that take place. In a chemical equation, the arrow indicates the direction of the reaction and is commonly depicted as a single arrow pointing from the reactants to the products. In contrast, the equals sign (=) is commonly used in mathematical equations to indicate that two expressions have the same value.
While numbers are used to indicate the relative proportions of reactants and products and minus signs are used to indicate reactants or products in the form of ions, the arrow is the most distinguishing feature that distinguishes chemical equations from mathematical equations.
7. Balance the following reaction under basic conditions: Al (s) + Cr2O72- (aq) -> Al3+ (aq) + Cr3+ (aq)
8. What is the ^o of the following balanced redox reaction (use the reduction potentials provided in Table 11.1
below)?
Fe3+ (aq) + Au (s) -> Fe (s) + Au3+ (aq)
9. What is G for the reaction below – calculate it from the ^o ?
Fe (s) + Au3+ (aq) -> Fe3+ (aq) + Au (s)
The free energy change of the reaction; Fe (s) + Au3+ (aq) -> Fe3+ (aq) + Au (s) is calculated to be -443.83KJ/mol.
For the reaction shown in question 7, we can divide it into half equations as follows;
Oxidation half equation;
6 Al (s) -------> 6Al^3+(aq) + 18e
Reduction half equation;
3Cr2O7^2-(aq) + 42H^+(aq) + 18e -----> 6Cr^3+(aq) + 21H2O(l)
The balanced reaction equation is;
6Al(s) + 3Cr2O7^2-(aq) + 42H^+(aq) -----> 6Al^3+(aq) + 6Cr^3+(aq) + 21H2O(l)
The E° of this reaction is obtained from;
E° anode = -0.04 V
E°cathode = +1.50 V
E° cell = +1.50 V - (-0.04 V) = 1.54 V
Given that;
ΔG° = -nFE°cell
n = 3, F = 96500, E°cell = 1.54 V
ΔG° = -(3 × 96500 × 1.54)
ΔG° = -443.83KJ/mol
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A student creates a hypothesis about their upcoming experiment. What must the
student do in their experiment with relationship to their hypothesis?
create a law based on the hypothesis
change the experiment to make the hypothesis correct
ignore the hypothesis
make observations to prove or disprove the hypothesis
Answer:
D. make observations to prove or disprove the hypothesis
Explanation:
What type of volcano is formed at a weak spot in the middle of a plate?
a.
lava
c.
hot spot
b.
fault
d.
plate
Hot spot volcano is the type of volcano which is formed at a weak spot in
the middle of a plate.
Hot spot volcano is an area in the Earth crust which is characterized by large
amount of heat flow in the area due to the volcanic activity. Hot spot
volcano is formed at the middle of the plate as against junctures in which
other types are formed.
The weak spot is what gives rise to the unusual heat flow which makes hot
spot volcano most appropriate.
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How many moles of Iron (III) Oxide are found in 429 grams of Iron III Oxide?
Answer:
2.686485288205376 Explanation:
1 grams Iron(III) Oxide is equal to 0.0062622034690102 mole.
In water is the mass of one molecule equal to the mass of one molecule in steam
Answer:
The mass of one mole of water molecule = 18 ×N
A amu
Explanation: The mass of one mole of water molecule = Mass of one molecule ×N A Also mass of one mole of water is its molar mass in grams. So the mass of one mole of water is 18 g
The diagram shows Earth's position in its orbit around the Sun at the beginning of each season
Which position of Earth shows the Moon located where its shadow may sometimes reach Earth?
The position where the moon is located where its shadow may sometimes reach Earth is position A .
What is an eclipse?We know that in the outer space there are a lot of celestial bodies that can be found. Now we know that a celestial body is one that can be found in the outer space and the moon and the sun are all parts of the celestial bodies that we can find in the solar system.
In this case we are being asked for the position of the moon that could lead to an eclipse where the moon would come between the earth and the sun and that is the position A.
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1. Atomic mass of 12 and 6 neutrons what is the atomic number?
Answer:
The atomic number would be 12.
Explanation:
A neutral atom of Carbon-12 contains six protons, six neutrons, and six electrons.
Jacinta wrote the following passage about chemical changes.
A chemical change is a change that results in one or more new substances with different properties. When a chemical change occurs, the new substance can give off an odor, such as rotting fruit or cookies baking in the oven. Chemical changes can cause color changes, such as iron rusting and turning a reddish-brown color. When wood is burned or ingredients are mixed for baking a cake, a new substance is made.
Choose the best statement that Jacinta can add to her passage.
Chemical changes, such as rotting fruit and burning wood, are affected by temperature. More heat and energy causes a faster chemical change.
Wood burning and fruit rotting creates new substances through a chemical change that is affected by sound energy.
Rotting fruit and burning wood is a chemical change that occurs because there is a decrease in temperature. Less heat causes a faster chemical change.
When a chemical change occurs, the new substance that is created has properties similar to the original substance.