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4 years ago

List 4 observations that suggest a chemical change is occurring

2 answers:

8 0

1. Creation of different compounds. (Since a chemical change is one in which the arrangement of atoms changes.)
2. Color change. ( Because if a new compound is formed, its color can be different from the original compound)
3. Cannot be reversed by reversing the condition.
4. In most cases, a gas is formed.

BabaBlast [244]4 years ago

4 0

1. The evolution of energy
2. the production of a gas
3. the formation of a precipitate
4. color change

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A) State the Law of Conservation of Matter.

Mariulka [41]

Answer:

matter can either be created nor destroyed but can be transmitted fromone state to another state

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3 years ago

Experiments are often performed in science to produce data or evidence. This evidence is then analyzed to draw conclusions. The

Deffense [45]

Answer: Scientific Methods

Explanation:

Scientific Methods means arriving at a valid conclusion based on overwhelming scientific evidences obtained through experiments. Science is empirical in its approach to seeking knowledge. Science encourages empiricism by its heavy reliance on experimental results in the construction of its arguments and arriving at its conclusions.

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3 years ago

Read 2 more answers

Forces that change an object motion by touching the object are _______ forces

strojnjashka [21]

Forces are pushes and pulls that may change the motion of an object. Balanced forces result in an object remaining at rest or moving at a constant speed. Unbalanced forces result in the acceleration of an object. An object's motion depends on how it changes position.

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3 years ago

Q2. 0.254 g of KHP (204 g/mol) titrated against 20.0 mL of unknown NaOH (40.0 g/mol) solution to get the end point of phenolpht

Vera_Pavlovna [14]

Answer:

Mass concentration (g/L) = 2.49g/L.

Explanation:

No. of moles = $\frac{mass}{molar mass}$

= $\frac{0.254}{204}$ = 0.001245 moles

Concentration of KHP (C1) in litres = n/v

= $\frac{0.001245}{0.02}$ = 0.062 mol/L

We know that:

$C_{1} V_{1}$ = $C_{2} V_{2}$

where c1v1 and c2v2 are the products of concentration and volumes of KHP and NaOH respectively.

Since mole ratio is 1 : 1.

1 mole of NaOH - 40g

0.001245 mole of NaOH = 40 × 0.001245 = 0.0498g

⇒0.0498g of NaOH was used during the titration

∴Mass concentration (g/L) = 0.0498g ÷ 0.02L

= 2.49g/L.

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3 years ago

How do you know what numbers in a chemical formula are significant

bulgar [2K]

Answer:

All the numbers in a chemical formula are significant, It is because the numbers in a chemical formula denote the number of different atoms present in the particular compound.

For example in H2SO4 there are 2 H 1 S and 4 O. This means 1 H2SO4 has 2 hydrogen 1 sulphur and 4 oxygen.

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3 years ago