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2 years ago

A good hypothesis allows you to make a testable prediction. Which of the following is an example of a good, testable prediction?

Chemistry

1 answer:

Elina [12.6K]2 years ago

8 0

Your answer would be B. If I add salt to ice cubes, they will melt faster.
I did this and got it right.

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Identify each substance as an acid or a base and write a chemical equation showing how it is an acid or a base according to the

faust18 [17]

Answer:

(a) Acid

(b) Base

(d) Base

Explanation:

According to the Arrhenius acid-base theory:

An acid is a substance that releases H⁺ in aqueous solution.

A base is a substance that releases OH⁻ in aqueous solution.

(a) H₂SO₄ is an acid according to the following equation:

H₂SO₄(aq) ⇒ 2 H⁺(aq) + SO₄²⁻(aq)

(b) Sr(OH)₂ is a base according to the following equation:

Sr(OH)₂(aq) ⇄ Sr²⁺(aq) + 2 OH⁻(aq)

(c) HBr is an acid according to the following equation:

HBr(aq) ⇒ H⁺(aq) + Br⁻(aq)

(d) NaOH is a base according to the following equation:

NaOH(aq) ⇒ Na⁺(aq) + OH⁻(aq)

6 0

2 years ago

Which of the following is similar among all living organisms on Earth?

statuscvo [17]

A. cellular function

hope this helps :)

5 0

2 years ago

For a particular reaction, ΔH∘=20.1 kJ/mol and Δ????∘=45.9 J/(mol⋅K). Assuming these values change very little with temperature,

tia_tia [17]

Answer:

The temperature should be higher than 437.9 Kelvin (or 164.75 °C) to be spontaneous

Explanation:

Step 1: Data given

ΔH∘=20.1 kJ/mol

ΔS is 45.9 J/K

Step 2: When is the reaction spontaneous

Consider temperature and pressure = constant.

The conditions for spontaneous reactions are:

ΔH <0

ΔS > 0

ΔG <0 The reaction is spontaneous at all temperatures

ΔH <0

ΔS <0

ΔG <0 The reaction is spontaneous at low temperatures ( ΔH - T*ΔS <0)

ΔH >0

ΔS >0

ΔG <0 The reaction is spontaneous at high temperatures ( ΔH - T*ΔS <0)

Step 3: Calculate the temperature

ΔG <0 = ΔH - T*ΔS

T*ΔS > ΔH

T > ΔH/ΔS

In this situation:

T > (20100 J)/(45.9 J/K)

T > 437.9 K

T > 164.75 °C

The temperature should be higher than 437.9 Kelvin (or 164.75 °C) to be spontaneous

7 0

3 years ago

Round off each number to the indicated number significant figures (sf):

qaws [65]

Answer :

(a) The given number in 2 significant figures will be, $3.6\times 10^3$

(b) The given number in 4 significant figures will be, $3.583\times 10^1$

(c) The given number in 3 significant figures will be, $2.24\times 10^1$

Explanation :

Significant figures : The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.

(a) The given number 00003554 converted into 2 significant figures.

In 00003554, there are 4 significant figures. Now we have to convert it into 2 significant figures.

The given number in 2 significant figures will be, $3.6\times 10^3$

(b) The given number 35.8348 converted into 4 significant figures.

In 35.8348, there are 6 significant figures. Now we have to convert it into 4 significant figures.

The given number in 4 significant figures will be, $3.583\times 10^1$

(c) The given number 22.4555 converted into 3 significant figures.

In 22.4555, there are 6 significant figures. Now we have to convert it into 3 significant figures.

The given number in 3 significant figures will be, $2.24\times 10^1$

7 0

2 years ago

Which subatomic particle do you think is most important to an atom’s identity?

Sonja [21]

The subatomic particle that identifies the atom is the number of protons. This is what distinguishes an element that is is flammmable, hydrogen to one that is essential component in water, oxygen.

5 0

3 years ago