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3 years ago

Help me out please? Thank you!

Chemistry

2 answers:

bixtya [17]3 years ago

5 0

First one because humidity, rainfall and cold are all characteristics of a continental zone.

aleksklad [387]3 years ago

4 0

Answer: Continental climates are classified by whether that fluctuates a lot. Hot summer, Cold winters and Little rainfall are all characteristics of Continental Climates

Explanation:

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Which characteristic should describe all evidence collected by a scientist?

scZoUnD [109]

Answer:

Option C

Objective

Explanation:

When dealing with the study of natural phenomena, a purely objective approach must be made by scientists. This is because natural phenomena exist, devoid of human feelings or emotions. There is no room for subjectivity as the natural occurrences do not vary based on human thoughts and perceptions; rather they exist on their own.

Therefore, every evidence collected by scientists should be objective and analysis should be made based on characteristics displayed and not from their previous experiences or personal point of view.

8 0

3 years ago

Name two physical properties that could be used to distinguish between water and ethanol.

miskamm [114]

Answer:

boiling point and melting point.

8 0

1 year ago

Explain how sand is form

Reptile [31]

Answer:

Sand comes from many locations, sources, and environments. Sand forms when rocks break down from weathering and eroding over thousands and even millions of years. Rocks take time to decompose, especially quartz (silica) and feldspar .

Explanation:

7 0

3 years ago

When a solid is heated up what occurs? A. The molecules move faster and become more dense B. The molecules move faster and becom

Xelga [282]

Answer: B. The molecules move faster and become less dense

Explanation:

Liquid is the state of matter in which particles are less tightly bound as compared to solids as they have weak inter molecular forces as compared to solids.

Thus when a solid is heated, the molecules start moving in random motion due to an increase in the kinetic energy. The molecules move apart as the forces will be weak and thus less molecules will be present per unit volume. Thus it will become less dense.

5 0

3 years ago

Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2 Mg(s) + O2(g) → 2 MgO(s) How many moles of O2 ar

TEA [102]

Answer:

1.05 mols of O2 gas

Explanation:

For this type of problem, it's important to understand what the balanced Chemical equation tells us:

<h3><u>Balanced Chemical equations</u></h3>

Let's look at the balanced chemical equation:

$2Mg(s)+O_2(g)-- > 2MgO(s)$

This equation two sides of the reaction arrow. On the left are the reactants (things you start with, and that react during the chemical reaction), and on the right side are products (things that are produced during the chemical reaction that you end with).

The numbers in front of each compound tell how many of molecules are involved for a full reaction without anything left over. A "mol" is a large quantity ( $6.022*10^{23}$ ), in this case, of molecules , since it's unlikely you're only taking a single molecule of each substance (it would be so tiny, you wouldn't even know you were doing the reaction).

So,for every 2 moles of Magnesium used, we'll also need 1 mole of Oxygen, and it will produce 2 moles of Magnesium Oxide.

In a way, during the reaction it's almost like 2 moles of Magnesium is equal to 1 mole of Oxygen and is equal to 2 moles of Magnesium Oxide:

$2 mol Mg(s)=1mol O_2(g)=2molMgO(s)$

From here, we can build some unit ratios, to convert between the known quantity of moles we have, and find the unknown quantity of moles that are requested.

<h3><u>Finding the right unit ratio</u></h3>

We know that we are looking at 2.10 mol of Magnesium, so we want a unit ratio with moles of Mg on the bottom. <u>We want to find moles of O2</u>, <u>so we want a unit ratio of moles of O2 on top</u>.

The unit ratio we want is the middle part of the equation, divided by the left part of the equation.

$2 mol Mg(s)=1mol O_2(g)\\\frac{2 mol Mg(s)}{2 mol Mg(s)}=\frac{1mol O_2(g)}{2 mol Mg(s)}\\1=\frac{1mol O_2(g)}{2 mol Mg(s)}$

Since this quantity is 1, it is a unit ratio and can be multiplied to other things to change their units (for this problem).

<h3><u>Finding the answer</u></h3>

Starting with what we know, and multiplying by our unit ratio:

$2.10 mol Mg(s)*\frac{1mol O_2(g)}{2 mol Mg(s)}=1.05mol O_2(g)$

Notice that the units from the first quantity cancel with the units on the bottom of the fraction, leaving only the unit on top of the fraction ... the exact units we wanted!

So, 1.05mols of O2 would be consumed during the reaction if exactly 2.10moles of Magnesium are burned.

4 0

3 years ago