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3 years ago

I need help with these two

Chemistry

1 answer:

bearhunter [10]3 years ago

3 0

Answer:

6. d, 7. a

Explanation:

6. Molarity is a number of moles solute in 1 L solution.

7. 1 L solution - 2.5 mol K2CO3

20 L - x mol K2CO3

x =20*2.5/1 = 50 mol K2CO3

Molar mass(KCO3) = M(K) + M(C) + 3M(O)= 39 +12 +3*16= 99 g/mol

99 g/mol *50 mol = 4950 g KCO3 Closest answer is A.

Actually KCO3 does not exist, in reality it should be K2CO3.

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By titration, it is found that 31.7 mL of 0.145 M NaOH(aq) is needed to neutralize 25.0 mL of HCl(aq). Calculate the concentrati

arlik [135]

Answer:

0.184 M

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

HCl + NaOH —> NaCl + H2O

From the balanced equation above, the following data were obtained:

Mole ratio of the acid, HCl (nA) = 1

Mole ratio of the base, NaOH (nB) = 1

Next, the data obtained from the question. This includes:

Volume of the base, NaOH (Vb) = 31.7 mL Molarity of the base, NaOH (Mb) = 0.145 M

Volume of the acid, HCl (Va) = 25.0 mL

Molarity of the acid, HCl (Ma) =?

Finally, we shall determine the molarity of the acid (HCl) as shown below:

MaVa /MbVb = nA/nB

Ma × 25 / 0.145 × 31.7 = 1

Cross multiply

Ma × 25 = 0.145 × 31.7

Ma × 25 = 4.5965

Divide both side by 25

Ma = 4.5965 / 25

Ma = 0.184 M

Therefore, the molarity of the acid (HCl) is 0.184 M

6 0

3 years ago

Jasper made a list of the properties of electromagnetic waves. Identify the mistake in the list.

ch4aika [34]

Answer:

B. Line 2 has a mistake

Explanation:

1. All electromagnetic waves are made of both electric and magnetic fields (hence the name electromagnetic).

2. All electromagnetic waves are transverse, and not longitudinal.

3. All electromagnetic waves can travel through space because they do not need particles to travel (like sound waves).

4. Electromagnetic waves all travel at the speed of light (299 792 458 m/s).

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3 years ago

A large, semi-truck hauling a full load and a small car are traveling in the same direction. As they approach a sharp curve in t

WARRIOR [948]

The semi will have the hardest time changing direction because of its mass. The more mass there is, the more effort it takes to accelerate and decelerate as well as change direction.

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3 years ago

The temperature

solniwko [45]

$\quad \huge \quad \quad \boxed{ \tt \:Answer }$

$\texttt {The reaction releases energy}$ $\texttt{( - or Exothermic)}$

____________________________________

$\large \tt Explanation \: :$

Temperature of thermometer increases during the reaction, that means it receives heat. henceforth we can conclude that energy is released during the reaction that cleary mean that it's an Exothermic Reaction.

Answered by : ❝ AǫᴜᴀWɪᴢ ❞

7 0

2 years ago

What is the wavelength of a wave having a frequency of 2500 Hz

Lemur [1.5K]

We will assume that the wave is moving in free space, thus, the velocity of the wave would be equal to the speed of light = 3 * 10^8 meters/sec

The velocity of the wave can be calculated using the following rule:
velocity = frequency * wavelength where:
velocity = 3 * 10^8 m/sec
frequency = 2500 Hz
wavelength is the unknown that we want to calculate.

Substitute with the givens in the above equation to get the wavelength as follows:
3 * 10^8 = 2500*wavelength
wavelength = 120 * 10^3 meters

5 0

3 years ago

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