All categories

3 years ago

PLS PLS PLS PLS HELP IM STRUGGLING

Chemistry

1 answer:

andriy [413]3 years ago

5 0

Answer:

A. 4 only

Explanation:

One of the tests for purity is by determining the melting point of a substance. A pure substance has a sharp meting point.

If the solid in question is a pure solid, when it is heated, it will exhibit a sharp melting point. Mixtures however melt over a range of temperatures due to the presence of impurities in the solid.

You might be interested in

The table shows the number of reactants and products present during two separate chemical reactions.

finlep [7]

Answer:

Chemical reaction B, because the product is a compound

Explanation:

A synthesis or combination reaction is that reaction that involves combination of two or more reactants to form a single product. The two or more reactants are often elements that chemically combine to form a single compound.

In this question, two chemical reactions are involved in which chemical reaction A has 1 reactants and 3 products while chemical reaction B has 2 reactants and 1 product. Based on the explanation above, the reaction B correctly identifies the synthesis reaction because the single product is a compound.

4 0

3 years ago

Sodium metal is sometimes used as a cooling agent in heat exchange units because of its relatively high molar heat capacity of 2

IgorC [24]

Answer:

The specific heat of sodium is 1,23J/g°C

Explanation:

Using the atomic weight of sodium (23g/mol) and the atomic weight definition, we have that each mole of the substance has 23 grams of sodium.

starting from this, we use the atomic weight of sodium to convert the units from J / mol ° C to J / g ° C

$28,2 \frac{J}{mol C} x \frac{1mol}{23g} = 1,23 J/g C$

4 0

3 years ago

Un catión trivalente contiene 75 nucleones y 45 neutrones, Señale el número de electrones que posee dicho catión.

FromTheMoon [43]

Answer:

10 electrons

Explanation:

5 0

3 years ago

Determine the mass of KNO3 that dissolves in 100 grams of water at 40°C to produce a saturated solution

velikii [3]

From a solubility curve the solubility of KNO3 at 40°C is about 63 g / 100 g of water.

That means that 100 g of water at 40°C can dissolve 63 g of KNO3.

A saturated solution is one that cannot dissolve more solute, because it already has reached the greatest concentration that it can hold.

Then, the mass of KNO3 that dissolves in 100 g of water is about 63 g.

5 0

3 years ago

If the caterpillar keeps moving at the same speed, how long will it take to travel 6cm?

Solnce55 [7]

It will take 15 s to travel 6 cm

<h3>Further explanation</h3>

Given

distance versus time graph

Required

time travel

Solution

Caterpillar motion is a straight motion with a constant speed, so that the graph between distance and time forms a diagonal line

If we look at the graph, we can determine the time taken when the distance reaches 6 cm (y axis) by drawing a line to the diagonal line and cutting the x-axis as time, and we get 15 s

Or we can also use the formula for motion at constant speed:

d = v x t

With v at point 2,5 of 2/5 m / s, so the time taken:

$\tt t=\dfrac{d}{v}=\dfrac{6}{2/5}=15~s$

4 0

3 years ago