Answer:
option a
Velocity is plotted on the x-axis of a graph and speed is plotted on the y-axis.
For the following diagram, select all statements that are true. (Picture provided)
According to given Information:
The energy change of the reaction is -20kJ is true statement, This is exothermic reaction.
What is exothermic?Exothermic meaning that the products of the reaction have lower energy than the reactants.
The negative value of the energy change (-20kJ) indicates that energy is released during the reaction.
What is energy change?Energy change refers to the difference in energy between the products and reactants of a chemical reaction. If the energy change is positive, it means that energy is absorbed by the reaction and the reaction is endothermic.
If the energy change is negative, it means the energy is released by the reaction and the reaction is exothermic. The magnitude of the energy change provides information about the amount of energy that is released or absorbed during the reaction
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uestion 8 Calculate the percentage by mass of hydrogen in PtCl2(NH3)2 A. 1.558 B. 1.008 c.0.672 D. 0.034 E.2.016
The percentage by mass of hydrogen can be calculated from the problem as 2.016
How do you calculate the mass percent of an atom in a compound?To calculate the mass percent of an atom in a compound, you first need to determine the molar mass of the compound and the molar mass of the atom of interest.
Determine the molar mass of the compound by adding up the atomic masses of all the atoms in the compound.
Determine the number of moles of the atom of interest in one mole of the compound. This is done by dividing the atomic mass of the atom by the molar mass of the compound.
We know that the relative molecular mas of the compound is; 300 g/mol
Then;
Percent by mass of hydrogen is; 6/300 * 100/1
= 2.016%
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After addition of 20.00 mL of 0.500 M standard KOH solution to 10.00 mL of formic acid (HCOOH, Ka = 1.8 × 10-4), the equivalence point is reached. What is the molarity of the formic acid?
What is the pH at the equivalence point, based on the question above? Please make a suggestion for an appropriate indicator.
Answer: 3.79
Explanation: The balanced chemical equation for the reaction between formic acid (HCOOH) and KOH is:
HCOOH + KOH → HCOOK + H2O
We can use the stoichiometry of this reaction to calculate the number of moles of formic acid that reacted with the KOH:
moles of KOH = (20.00 mL)(0.500 mol/L) = 0.01000 moles
moles of HCOOH = moles of KOH
Therefore, the initial number of moles of formic acid is:
moles of HCOOH = (10.00 mL)(x mol/L) = 0.01000 moles
where x is the molarity of formic acid.
Solving for x, we get:
x = 1.00 M
Therefore, the molarity of the formic acid is 1.00 M.
At the equivalence point, all of the formic acid has reacted with the KOH, and the solution contains only the salt formed by the reaction, potassium formate (HCOOK). The pH at the equivalence point can be calculated using the equation for the salt hydrolysis constant:
Kb = Kw/Ka
where Kb is the base dissociation constant of the conjugate base (formate ion), Kw is the ion product constant for water (1.0 × 10^-14 at 25°C), and Ka is the acid dissociation constant of the acid (formic acid). Rearranging this equation, we get:
Kb/Ka = [OH^-][HCOO^-]/[HCOOH]
At the equivalence point, the concentration of the formate ion (HCOO^-) is equal to the concentration of the KOH added (0.01000 moles / 30.00 mL = 0.3333 M). We can assume that the concentration of the hydroxide ion (OH^-) is also equal to 0.3333 M, since KOH is a strong base and will dissociate completely. Substituting these values into the equation above, we get:
Kb/Ka = (0.3333)^2 / [HCOOH]
Solving for [HCOOH], we get:
[HCOOH] = (0.3333)^2 / (1.8 × 10^-4) = 6181.5 M
Taking the negative logarithm of this concentration, we get the pH at the equivalence point:
pH = -log[HCOOH] = -log(6181.5) = 3.79
Therefore, the pH at the equivalence point is 3.79.
Regenerate response
A student used a balance and a graduated cylinder to collect the data 10.23,20.0, and 21.5 calclulate the density of the elements
Assuming that the student measured the mass of the elements using a balance and the volume using a graduated cylinder, we can use the following formula to calculate the density:
Density = mass / volume
Let's say the masses of the elements were 10.23 grams, 20.0 grams, and 21.5 grams, and the volumes were 10 mL, 20 mL, and 25 mL respectively.
Then, the densities would be:
Density of element 1 = 10.23 g / 10 mL = 1.023 g/mL
Density of element 2 = 20.0 g / 20 mL = 1.0 g/mL
Density of element 3 = 21.5 g / 25 mL = 0.86 g/mL
What is density?
Density is a physical property of matter that describes how much mass is contained in a given volume of a substance. It is defined as the amount of mass per unit volume, and is typically measured in grams per cubic centimeter (g/cm³) or kilograms per cubic meter (kg/m³).
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Which of these is not a sign of a chemical reaction?
1. The material dissolves
2. Heat is released
3. A gas is given off
A chemical reaction is known by;
2. Heat is released
3. A gas is given off
How do you know a chemical reaction?A change in color may indicate that a chemical reaction has occurred. For example, when iron is exposed to air and moisture, it rusts and turns from silver to reddish-brown.
If a gas is produced during a reaction, it can indicate that a chemical reaction has occurred. For example, when baking soda is mixed with vinegar, carbon dioxide gas is produced, which causes bubbles to form.
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Please help almost due?
Answer:
-lithium
-atomic number
-mass number
-protons
Explanation: