Is making salt water to gurgle for a sore throat a physical or chemical change

A 0.1025-g sample of copper metal is dissolved in 35 ml of concentrated hno3 to form cu2 ions and then water is added to make a

GalinKa [24]

Molarity is defined as number of moles of solute in 1 L of solution.

Here, 0.1025 g of Cu is reacted with 35 mL of HNO_{3} to produced Cu^{2+} ions.

The balanced reaction will be as follows:

Cu+3HNO_{3}\rightarrow Cu(NO_{3})_{2}+NO_{2}+H_{2}O

From the above reaction, 1 mole of Cu produces 1 mole of Cu^{2+}, convert the mass of Cu into number of moles as follows:

n=\frac{m}{M}

molar mass of Cu is 63.55 g/mol thus,

n=\frac{0.1025 g}{63.55 g/mol}=0.0016 mol

Now, total molarity of solution, after addition of water is 200 mL or 0.2 L can be calculated as follows:

M=\frac{n}{V}=\frac{0.0016 mol}{0.2 L}=0.008 mol/L=0.008 M

Thus, molarity of Cu^{2+} is 0.008 M.

7 0

3 years ago

If a man has a mass of 83 kilograms on Earth, what will the force of gravity on his body be on the moon?

VladimirAG [237]

The answer is (A.) 135.6 N

————

Here is the formula you will need to answer the question.

Formula:
Force(N) = Mass(kg) x Acceleration(m/s²)
or... F(N) = m(kg) x a(m/s²)

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We need to be certain of the information presented. The problem says the man has a "Mass" of 83 kilograms on Earth. If a man has a Mass of 83 kilograms on Earth, he has a mass of 83 kilograms everywhere. The mass for this problem (even on the moon) is 83.

Mass(kg): 83

————

To find the acceleration of object on other planets, moons, ect, you'll need to search the internet or ask a teacher. There are ways to calculate this, but the problem didn't supply the necessary information to do so.

Acceleration: 1.625 m/s²

————

Now just plug the information into the formula.

F(N) = m(kg) x a(m/s²)

N = 83 x 1.625
N= 135.875

When considering that there could be a slighty more accurate number for acceleration, it can be concluded that the best answer is (A.)

3 0

4 years ago

____ 26. what is the weight percentage of nitrogen in urea, cn2h4o

Paraphin [41]

Weight percentage of nitrogen can be calculated using the following rule:
weight percentage of nitrogen = (weight of nitrogen / weight of urea) x 100

From the periodic table:
molecular mass of carbon = 12 grams
molecular mass of nitrogen = 14 grams
molecular mass of hydrogen = 1 grams
molecular mass of oxygen = 16 grams

therefore:
mass of nitrogen in urea = 2(14) = 28 grams
mass of urea = 12 + 2(14) + 4(1) + 16 = 60 grams

Substitute with the masses in the equation to get the percentage:
weight percentage of nitrogen = (28/60) x 100 = 46.667%

7 0

4 years ago

What are lower and higher energy levels.

kozerog [31]

Answer:

If an atom, ion, or molecule is at the lowest possible energy level, it and its electrons are said to be in the ground state. If it is at a higher energy level, it is said to be excited, or any electrons that have higher energy than the ground state are excited

Explanation:

pls mark brainliest

8 0

3 years ago

WILL GIVE THE BRAIN THING-

Kruka [31]

Answer:

The products are Al(NO₃)₃(aq) and H₂(g).

Al(s) + 3 HNO₃(aq) ⇒ Al(NO₃)₃(aq) + 1.5 H₂(g)

Explanation:

Let's consider the reaction between aluminum and nitric acid. This is a single replacement reaction, in which Al replaces H in HNO₃ to form aluminum nitrate. The unbalanced reaction is:

Al(s) + HNO₃(aq) ⇒ Al(NO₃)₃(aq) + H₂(g)

We start balancing N atoms by multiplying HNO₃ by 3.

Al(s) + 3 HNO₃(aq) ⇒ Al(NO₃)₃(aq) + H₂(g)

Finally, we get the balanced equation multiplying H₂ by 1.5.

Al(s) + 3 HNO₃(aq) ⇒ Al(NO₃)₃(aq) + 1.5 H₂(g)

5 0

3 years ago