CHEMISTRY HIGH SCHOOL

When determining whether a chemical reaction has taken place you observe and look for several indicators. Which would be considered an indication that a chemical reaction or chemical change has taken place? es -) A) Solid melts. B) Heat is given off. Substance dissolves D) Substance changes shape. Physical Science​

Answers

Answer 1
Answer:

Answer:

B) Heat is given off.

Explanation:

When heat is given off, a chemical change must have occurred and such a reaction is termed an exothermic reaction.

A chemical change is one in which;

  • the process is not easily reversible
  • leads to the production of new kinds of matter
  • involves change in mass
  • requires a considerable amount of energy.

Most chemical reactions are accompanied by heat changes.

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An object has a density of 1.75 g/mL. Will it float on water? Why?

Answers

Answer:

The object will not float in water because the density of the object is greater than that of water.

Explanation:

Density of object = 1.75 g/mL

Density of water = 1 g/mL

The Density of the object is 1.75 g/mL and that of water is 1 g/mL. This implies that the object is denser (i.e heavier) than water. Therefore, the object will not float in water, rather it will sink in water since it's density is greater than that of water.

A rock is dropped into a graduated cylinder containing 40mL of water. the new volume is 47mL. What is the volume of the rock? a)4ml b)47ml c)7ml d)87ml e)11mlI thibk it is 7ml am I correct ?

Answers

The volume of the rock is 7mL. The correct option is c)7ml

From the question,

We are to determine the volume of the rock.

When an object is submerged in a container containing a liquid, the submerged object displaces a volume of liquid equal to the volume of the object.

That is,

Volume of object = Final volume - Initial volume

From the given information,

Initial volume = 40mL

Final volume = 47mL

∴ Volume of the rock = 47mL - 40mL

Volume of the rock = 7mL

Hence, the volume of the rock is 7mL. The correct option is c)7ml

Learn more here: brainly.com/question/10136572
To find the volume of irregularly shaped objects, you put them in graduated cylinders, as described. To find the volume of the object, get the difference between the original volume and the new volume. 
So, its 47mL - 40mL, which equals 7, so choice c) 7mL, the answer you picked!

Which of the following is true of solids?a. All solids have equal melting points.
b. Ionic solids have higher melting points than molecular solids.
c. Molecular solids have higher melting points than all other types of solids.
d. It is impossible for solids to melt; therefore solids do not have melting points.

Answers

B. Ionic solids have higher melting points than molecular solids.

Two liquids mix, neither absorbing nor releasing heat.

Answers

When two liquids mix without absorbing or releasing heat, it's referred to as an ideal mixing process. This means that the temperature of the mixture remains constant throughout the process, and there is no change in enthalpy (heat content) of the system. In thermodynamics, this type of mixing is often described as an isenthalpic process. It occurs when the mixing process is perfectly efficient and doesn't involve any heat exchange with the surroundings. This phenomenon can be observed in some real-world situations, but it's an idealized concept used in thermodynamic calculations.

When two liquids mix without absorbing or releasing heat, it is an isothermal process where the temperature of the mixture remains constant. A common example is mixing water and ethanol.

When two liquids mix without absorbing or releasing heat, it means that the mixing process is isothermal. This is because the temperature of the mixture remains constant throughout the process.

One example of this is when you mix equal amounts of water and ethanol. Both liquids have similar intermolecular forces, so they mix easily. The temperature of the mixture remains the same as the initial temperature of the liquids.

Learn more about isothermal at

brainly.com/question/31330231

#SPJ11

Which begins as radiant energy and can be transformed into electricity? A.
water

B.
uranium

C.
sunlight

D.
wind

Answers

A. water. hope i helped
A. water is the most likly choice for the answer

Which of the following is not a valid conversion factor? 1/100 centimeter 1mL/1cm^3 1kilometer/1000 meters 1meter/10 milimeters

Answers

1meter/10 milimeters which should be 1000 mm

1m=1000mm

International System of Units (SI Units) are organized body of measurements for physical quantity. They are set to be the norm or global norm scaling for every physical quantity which includes kilogram, meter, second, ampere, kelvin, candela and mole. These measurements then can increase or decrease by the power of ten, multiplied or divided. As said and explained, the SI is helpful in describing objects because 
1.       They give us the idea of how much matter is contained in that single substance or the current state the matter is in or how hot or cold. We measure and can quantify the quality of the specific matter. 
2.       SI Units are a global set of measurement hence, we can communicate with ease from western to eastern countries with these measurements without having problems in terms of portraying or displaying a set of physical quantities. 

Answer:hello

Explanation:

Task masters

Is correct! It should be answer(4) or (D)

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