True or false questions?
Most metal elements are brittle and do not conduct electricity. True or False
Any element can be identified by counting the protons in its neucleus. True or False
All Earths matter is made from the combination of about 100 elements. True or false

Answer:

Nickel

Explanation:

Given data:

Density of iron = 7.9 g/cm³

Density of lead = 11.3 g/cm³

Density of nickel = 8.9 g/cm³

Mass of sample = 134 g

Volume of sample = 15 cm³

Which metal it is = ?

Solution:

First of all we will calculate the density of sample and then match it with the density of given metals.

Formula:

d = m/v

by putting values,

d = 134 g/ 15 cm³

d = 8.9 g/cm³

The weighted sample is nickel metal.

Answer:

The core turns its hydrogen to helium and stops nuclear fusion which causes the outer shells of hydrogen to collapse.

Explanation:

This results in higher temperature and pressure which in turn causes the outer shells to expand and cool as a red giant.

Answer:

See answer below

Explanation:

a.) Lithium Chloride, LiCl is soluble in water.

b.) Silver Chloride, AgCl is insoluble in water.

c.) Barium Carbonate, BaCO3 is insoluble in water.

d.)Potassium, K2 is soluble in water.

e.) Iron (III) Nitrate Fe(NO3)3 is soluble in water.

Answer: D

Explanation:

Cause If you head to the middle of the ocean and dive down, down, down to where the Earth's plates meet, you might find an undersea mountain split by a deep trench. It's called a mid-ocean ridge. Up through such trenches, brand-new molten rock is bubbling. That's the newest rock on Earth! How does the ocean floor make room for all that new rock? Simply by pushing the old rock aside. In fact, the ocean floor is actually spreading right at this minute, out away from the deep trenches where new rock is being formed. The oldest rock can be found farthest away from the trenches, right up near the continents. It's all part of a process called seafloor spreading. It's been going on for millions of years (at the rate of a few centimeters per year), but scientists are just now getting to know more about it. In fact, because evidence of seafloor spreading was first discovered in the 1940s and 50s, your great-grandparents may have never heard of it!

Answer:

1 g/cm3

Explanation:

The formula for density is mass/volume

The mass is 100 g and the volume is 100 cm3

100 g/100 cm3=1 g/cm3

Answer:

No. of moles = 0.0685

Explanation:

Given mass, m = 15.5g

We need to find the number of moles in 15.5 g of CaSO₄.5H2O

First, we find the mass of CaSO₄.5H2O.

M = (1×40)+(1×32)+(4×16)+(5×18)

M = 226 g/mol

We know that,

Number of moles = given mass/molar mass

[tex]n=\dfrac{15.5\ g}{226\ g/mol}\\\\n=0.0685\ \text{mol}[/tex]

Hence, there are 0.0685 moles in 15.5 g of CaSO₄.5H2O.

Answer:

6.576 g NaCl

Explanation:

2Na + Cl2 --> 2 NaCl

Step 1: Find out moles of Na and Cl to determine the limiting reactant:

moles Na = 12/23 = 0.52 moles Na

moles Cl2 = 16/71=0.225 moles Cl2

ratio Na:Cl is 2.3:1 so Cl is the limiting reactant.

Step 2: How many moles of NaCl are formed:

moles NaCl = moles Cl2 x (1 mol NaCl/2 moles Cl2) = 0.225/2 = 0.1125 moles NaCl

Step 3:

mass NaCl = moles NaCl x MM NaCl = 0.1125 x 58.45 = 6.576 g NaCl

Answer:

See explanation below

Explanation:

In this case, we can use the Boyle's law. Assuming that the temperature of both trial remains constant, then:

P₁V₁ = P₂V₂    (1)

You should note that this expression is usable when you are dealing with gases. However, we can treat this unknown liquid as a gas, because all the air on the flask is removed, and we can assume that the liquid can behave like an ideal gas.

So using the above expression, we can solve for P₂:

P₂ = P₁V₁ / V₂    (2)

In this case, we already have the values of presures and volume, so replacing in this expression:

P₂ = 34.5 * 5 / 214

This should be the pressure of the liquid.

Hope this helps

Answer:

one mole of oxygen will produce [tex]0.4[/tex] moles of water

Explanation:

The balanced chemical reaction is as follows -

2 C2H2 + 5 O2 --> 4 CO2 + 2 H2O

As we can see in this reaction

5 mole of oxygen (on the reactant side) will produce 2 mole of water (on the product side)

Hence, one mole of oxygen will produce [tex]\frac{2}{5} =0.4[/tex] moles of water

Explanation:

w is the stage in which dna is copied and cell grows.

Answer:

w

Explanation:

Answer:

law of multiple proportions

Explanation:

The law of multiple proportions states that, if two elements A and B, combine to form more than one chemical compound. Then the various masses of one element A, which combine separately with a fixed mass of element B are in  simple multiple ratio.

We can see that the ratio of oxygen that combines with carbon in the two compounds( A and B) is 1:2. This demonstrates the law of multiple proportions.

The substances A and B must be CO and CO2 respectively.

Answer:

The answer is "[tex]\bold{263 \ and \ 137.1 \frac{g}{ mol}}[/tex]".  

Explanation:

The chemical formula for Salicylamide: [tex]C_7H_7NO_2[/tex]

[tex]\to (12.011 \ \frac{g}{mol} \times 7)+(1.008 \ \frac{g}{mol} \times 7)+(14.0067 \frac{g}{mol} \times 1)+(15.999 \frac{g}{mol} \times 2) \\\\\to (84.077 \ \frac{g}{mol} )+(7.056 \ \frac{g}{mol} )+(14.0067 \frac{g}{mol})+(31.998 \frac{g}{mol} ) \\\\\to (84.077 \ \frac{g}{mol} )+(7.056 \ \frac{g}{mol} )+(14.0067 \frac{g}{mol})+(31.998 \frac{g}{mol} ) \\\\ =137.1377 \approx 137.1\ \frac{g}{mol}[/tex]

The chemical formula of Iodosalicylamide:[tex]C_7H_6INO_2[/tex]

[tex]\to (12.011\frac{g}{mol}\times 7)+(1.008\frac{g}{mol}\times 6)+(126.904\frac{g}{mol}\times 1)+(14.0067\frac{g}{mol}\times 1)+(15.999\frac{g}{mol}\times 2) \\\\\to (84.077\frac{g}{mol})+(6.048\frac{g}{mol})+(126.904\frac{g}{mol})+(14.0067\frac{g}{mol})+(31.998\frac{g}{mol}) \\\\=263.0337 \approx 263.0\ \frac{g}{mol}[/tex]

Answer:

See explanation

Explanation:

A positron is also called a positive electron. It results from the transformation of a proton into a neutron.

When a nucleus decays by positron emission, the atomic mass of both the parent and daughter nuclei remain the same but the atomic number of the daughter nucleus decreases by 1 compared to that of the parent nucleus. The daughter nucleus is now found one place to the left of the parent nucleus in the periodic table.

This leads to an increase in the Neutron/Proton ratio.

Given

Atomic symbol

Required

Atomic composition

Solution

Atomic number = number of protons = number of electrons

Mass Number (A) is the sum of protons and neutrons

Number of protons and Number of Neutrons  in nucleus

Number of electrons in the shell

From the picture:

protons = 3

neutrons = 4

electrons = 3

atomic number = protons = electrons = 3

mass number = protons + neutrons = 3+4 = 7

Answer:

atoms

Explanation:

i hope that help you

Answer:

atoms

Explanation:

Answer: Decrease in size

Explanation:

Electronegativity is defined as the property of an element to attract a shared pair of electron towards itself.

On moving across a period from left to right,   the size of an atom decreases because the electrons get added to the same shell and the nuclear charge keeps on increasing. Thus the electrons get more tightly held by the nucleus.

As, the size of an element decreases, the valence electrons come near to the nucleus. So, the attraction between the nucleus and the shared pair of electrons increases. Thus electronegativity increases.

Answer:

products

Explanation:

yeah the answer is product

Answer:

439.7nm

Explanation:

Energy of a quantum can be calculated using below formula

E=hv...........eqn(1)

But v=λ/ c .........eqn(2)

If we substitute eqn(2) into eqn(1) we have

E= hc/(λ)

Where E= energy

h= Plank's constant= 6.62607004 × 10-34 m2 kg / s

c= speed of light

c= 2.998 × 10^8 m/s

λ= wavelength= ?

But the energy was given in Kj , it must be converted to Kj/ photon for unit consistency.

Energy E= 272 kJ/mol × 1mol/6.02× 10^23

Energy= 451.83× 10^-24 Kj/ photon

E= hc/(λ)...........eqn(1)

If we make λ subject of the formula

λ= hc/E

Then substitute the values we have

λ= [(6.626 × 10^-34) × (2.998 × 10^8)]/451.83× 10^-24

λ=(0.00043965) × (1Kj/1000J) × (10^9nm/1m)

λ=439.7nm

Hence, the longest wavelength of radiation with enough energy to break carbon-sulfur bonds is 439.7nm

Answer:

See explanation below

Explanation:

In this case we have reaction of addition. In this case a diene reacting with an acid as HBr. This reaction is known as Hydrohalogenation, and, as we have a diene, this kind of reaction can be done as 1,4 addition. Which means that the reaction will be undergoing with an adition in the carbon 1, and carbon 4.

At room temperature we can expect that this reaction can be done in thermodynamic conditions, Now, as the problem states that is forming 4 products, we can expect products of a 1,2 addition too. This product can be formed if the reaction is taking place in the most stable carbocation, and then, by resonance, we can expect the 1,4 product too.

Now, the HBr can be attacked by the double bond of the first position, giving two possible products or by the double bond of the third position giving the other two products. These products are all possible, obviously the most stable will be the major of all of them, but the other three are perfectly possible. One product is formed without doing much, and the other by resonance. Same happens with the other double bond.

In the picture below, you have the mechanism for all the 4 products.

Hope this helps

Answer:

Absolute error in measurement of A = 0.3

Absolute error in measurement of B = 0.3

Explanation:

Absolute error is a measure of the amount of error in a measurement i.e. a measure of how far away a measurement is from a true value or an indication of the uncertainty in a measurement.

The Absolute Error is the difference between the actual and measured value. In formula, the absolute error, Δx is given as:

Δx = |xi – x|,

Where:  xi is the measurement, x is the true value,

| | indicates that only absolute values are taken

In the measurements by the student in the question:

Metal Cylinder A

measured value = 12.4 grams

actual mass of metal cylinder A = 12.7 g

Using the absolute error formula; Δx = |xi – x|

Absolute error in measurement of A = |12.4 - 12.7| = 0.3

Metal Cylinder B

measured value = 75.4 grams

actual mass of metal cylinder B = 75.1 g

Using the absolute error formula; Δx = |xi – x|

Absolute error in measurement of B = |75.4 - 75.1| = 0.3

Answer:

0.378 g of H₂₂O can be produced.

Explanation:

The combustion reaction is:

2CH₃(CH₂)₂CH₃  +  13O₂  →  8CO₂  +  10H₂O

We convert the mass of reactants to moles:

0.58 g . 1mol / 58.1g = 0.00998 moles of butane

0.874 g . 1mol / 32g = 0.0273 moles of O₂

Oxygen is the limiting reactant. Look at stoichiometry.

2 moles of butane need 13 moles of oxygen to react

Then, 0.00998 moles of gas may react to (0.00998 . 13) / 2 = 0.06487 moles of oyxgen. I only have 0.0273 moles, so i do not have enough oxygen to complete the reaction.

Let's find out the product.

13 moles of oyxgen can produce 10 moles of water.

Then 0.0273 moles of O₂ may produce (0.0273 . 10)/13 =  0.021 moles

We convert to mass  →  0.021 mol . 18g /1mol = 0.378 g

Answer:

The mouth uses both mechanical and chemical digestion. Mechanical digestion involves physically breaking down the food into smaller pieces (using the jaw/teeth). However, chemical digestion then takes over and starts breaking down the food into simpler nutrients that can be used by the cells using saliva, which is naturally made within the mouth.

Hope this helps you! Have a great day! :D

Answer:

monosaccharides and glycosidic, I think

Explanation:

Answer:

pasagottt po plss

Explanation:

edi wow

Chief Keef - Love Sosa

Answer:

an aquifer is a renewable resource

Explanation:

Aquifers are defined as the groundwater found deep in the layers of rocks.

An aquifer is considered as a renewable resource because groundwater is renewed over time. Aquifers are water resources and follow hydrological cycle through which it can renew itself.

Some of the deep aquifers are considered as  nonrenewable resource because it toll hundreds of years to accumulate.

Hence, the correct answer is yes an aquifer is a renewable resource except some deep aquifers.

Answer:the first one is D second one is A and the third one is A   :D

Explanation: