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3 years ago

Endothermic or exothermic?

Chemistry

1 answer:

Tju [1.3M]3 years ago

6 0

Answer:

Endothermic

Exothermic

Endothermic

Exothermic

Explanation:

Endothermic is when a reaction absorbs heat.

Exothermic is when a reaction releases heat.

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Sample A: 300 mL of 1M sodium chloride

yarga [219]

Answer:

sample B contains the larger density

Explanation:

Given;

volume of sample A, V = 300 mL = 0.3 L

Molarity of sample A, C = 1 M

volume of sample B, V = 145 mL = 0.145 L

Molarity of sample B, C = 1.5 M

molecular mass of sodium chloride, Nacl = 23 + 35.5 = 58.5 g/mol

Molarity is given as;

$C = \frac{moles \ of \ solute, \ mol}{liters \ of \ solvent} \\\\Moles \ of \ solute \ for \ sample \ A = 1 \times 0.3 = 0.3 \ mol\\\\Moles \ of \ solute \ for \ sample \ B = 1.5 \times 0.145 = 0.2175 \ mol$

The reacting mass for sample A = 0.3mol x 58.5 g/mol = 17.55 g

The reacting mass for sample B = 0.2175 mol x 58.5 g/mol = 12.72 g

The density of sample A $= \frac{mass}{volume} = \frac{17.55}{0.3} = 58.5 \ g/L$

The density of sample B $= \frac{mass}{volume} = \frac{12.72}{0.145} = 87.72 \ g/L$

Therefore, sample B contains the larger density

5 0

3 years ago

Evaporación del alcohol cambio físico o químico?

Vlada [557]

Physical because you can see it evaporate have a great día

7 0

3 years ago

When a person in the hospital is given fluids intravenously, the fluid is typically a saline (salt) solution with about the same

Sati [7]

Answer:

Swelling of the red blood cells occurs.

Explanation:

Distilled water makes the blood hypotonic ,. that is a less concentrated solution, to the body tissues including the red blood cells.
Therefore the water will enter the red blood cells and may cause them to lyse or swell.
Additionally , water will enter the tissue spaces and cause sweling.
But in the case of a hypertonic solution , ( a salt or saline solution ) , This swelling does not happen because the concentration of the saline will be equal or more than the blood. 
Thus the water will flow only from the blood to the solution. This will not cause swelling.
But too much of salt is also not recommended.

5 0

3 years ago

What is the volume, in milliliters, occupied by 30.07 g of an object of density equal to

den301095 [7]

Answer:

$\boxed {\tt 20.317567567568 \ mL}$

Explanation:

The density formula is:

$d=\frac{m}{v}$

Let's rearrange the formula for $v$ . the volume. Multiply both sides by $v$ , then divide by $d$ .

$d*v=\frac{m}{v}*v$

$d*v=m$

$\frac{d*v}{d}=\frac{m}{d}$

$v=\frac{m}{d}$

The volume can be found by dividing the mass by the density. The mass of the object is 30.07 grams and the density is 1.48 grams per milliliter.

$m= 30.07 \ g\\d= 1.48 \ g/mL$

$v=\frac{30.07 \ g}{1.48 \ g/mL}$

Divide. Note, when dividing, the grams, or $g$ will cancel out.

$v= \frac{30.07}{1.48 \ mL}$

$v=20.317567567568 \ mL$

The volume of the object is 20.317567567568 milliliters.

3 0

4 years ago

what has 4 valence electrons, shows properties of metals and non metals, and has 32 protons in the nucleus of each atom

12345 [234]

Here is your answer

$\bold{Germanium}$

REASON:

Elements which have 4 valence electrons are generally metalloids.

The metalloids show the properties of both metals and non-metals.

We know that,

no. of protons= Atomic number

So,

Atomic no.= 32

Hence,

The element is Germanium which is a metalloid with 4 valence electrons and has 32 protons in nucleus of each atom because it has atomic no. 32

HOPE IT IS USEFUL

6 0

4 years ago