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4 years ago

Complete the sentence. Select all that apply. In the vertical columns of the periodic table:

Chemistry

2 answers:

Sever21 [200]4 years ago

3 0

All of them are pretty correct except the last one, can't really give you a definite answer sorry. <span />

IgorC [24]4 years ago

3 0

Answer: Atomic weight increases from top to bottom and the number of shells increases from top to bottom

Explanation: As we go down the group that is vertical column, atomic weight increases as atomic number is increasing.

Moreover the number of electrons in the outershell does not increases but the number of shells increases from top to bottom as atomic number are increasing and electrons are increasing thus more number of shells are needed to fill these electrons.

Physical Properties doesnot remain identical as they do changes on going down the groiup.

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How many moles are equal to 89.23g of calcium oxide, CaO?

Katen [24]

1.59moles

Explanation:

Mass of CaO = 89.23g

Unknown

Number of moles = ?

Solution:

The mole is a unit of measurement in chemistry used to delineate the number of particles an atom contains.

A mole of a substance contains the avogadro's number of particles.

Number of moles = $\frac{mass}{molar mass}$

Molar mass of CaO = 40 + 16 = 56g/mol

Number of moles = $\frac{89.23}{56}$ = 1.59moles

learn more:

Number of moles brainly.com/question/1841136

#learnwithBrainly

8 0

3 years ago

The temperature of evaporation is much higher for water than for alcohol. Without knowing more about the chemistry of alcohol, w

3241004551 [841]

Answer:

Explanation:

Alcohols are organic molecules characterized majorly by the presence of the OH group in their molecule. The OH group is majorly responsible for several of their characteristics. This include the formation of hydrogen bonds between alcohol molecules. While this makes them more inorganic than most organic compounds, comparatively the hydrogen bonding formed in alcohols is not as strong as that which is present in water.

The higher strength of the hydrogen bonding is responsible for some comparable properties. While water boils at a temperature of 100 degrees Celsius, alcohol boils at a temperature of 78 degrees Celsius. This is an evidence to the fact that hydrogen bonding in alcohol is less stronger that that in water.

4 0

3 years ago

Assume that a daily diet of 2000 calories (i.e. 8.37 x 106 J) is converted completely to body heat.

slava [35]

Answer:

(a) the mass of the water is 3704 g

(b) the mass of the water is 199, 285.7 g

Explanation:

Given;

Quantity of heat, H= 8.37 x 10⁶ J

Part (a) mass of water (as sweat) need to evaporate to cool that person off

Latent heat of vaporization of water, Lvap. = 2.26 x 10⁶ J/kg

H = m x Lvap.

$m = \frac{H}{L._{vap}} =\frac{8.37 * 10^6.J}{2.26*10^6\ \frac{J}{kg}} = 3.704 \ kg$

mass in gram ⇒ 3.704 kg x 1000g = 3704 g

Part (b) quantity of water raised from 25.0 °C to 35.0 °C by 8.37 x 10⁶ J

specific heat capacity of water, C, 4200 J/kg.°C

H = mcΔθ

where;

Δθ is the change in temperature = 35 - 25 = 10°C

$m =\frac{H}{c* \delta \theta} = \frac{8.37 *10^6}{4200*10} = 199.2857 kg$

mass in gram ⇒ 199.2857 kg x 1000 g = 199285.7 g

5 0

3 years ago

So, a gas, and an

valina [46]

Answer:

d) cut the large sized Cu solid into smaller sized pieces

Explanation:

The aim of the question is to select the right condition for that would increases the rate of the reaction.

a) use a large sized piece of the solid Cu

This option is wrong. Reducing the surface area decreases the reaction rate.

b) lower the initial temperature below 25 °C for the liquid reactant, HNO3

Hugher temperatures leads to faster reactions hence this option is wrong.

c) use a 0.5 M HNO3 instead of 2.0 M HNO3

Higher concentration leads to increased rate of reaction. Hence this option is wrong.

d) cut the large sized Cu solid into smaller sized pieces

This leads to an increased surface area of the reactants, which leads to an increased rate of the reaction. This is the correct option.

5 0

3 years ago

Red, green and blue light all have the same frequency and wavelength. True or false

Sedaia [141]

False, they are all different because they help you know different things.

4 0

3 years ago