You

2. An all natural mosquito repellent

is trying to make its way into the

market. One arm is sprayed with the

repellent and one arm is not sprayed

with anything. After 3 hours, the

number of mosquito bites is counted. What is the control group

Answer: 3

Explanation:

Answer:

kinetic energy

Explanation:

may be iam not sure

Answer:

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\ [/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

[tex]n = \frac{7.15 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 11.87707641...[/tex]

We have the final answer as

Hope this helps you

Answer:

a) The balloon filled with helium will float higher because helium is less dense than gas X

Explanation:

Since gases are known to not have fixed density, they take up the density of their containers, let us find the density of the gas in first balloon.

 Density is the mass per unit volume;

         Density  = [tex]\frac{mass}{volume}[/tex]  

Insert the parameters and solve;

    mass of gas  = 7.52g

     volume of the gas  = 27.8L

          Density  = [tex]\frac{7.52}{27.8}[/tex]   = 0.271g/L

Let us compare the two densities;

 Density of gas  = 0.271g/L

 Density of helium  = 0.179g/L

We see that the density of the gas is higher than that of helium, so, it not float as high as the balloon with helium. The balloon with helium is lighter.

Answer:

helllllooooooo hi how is life

Answer:

hiiii

Explanation:

Answer:

c

Explanation:

I believe its c but i could be wrong sorry if I am

Answer:

Equal

Explanation:

Energy is always conserved in the nature and it is an universal law. According to the law conservation of energy, it is said that energy can never be created out of something and we can never destroy and vanish any energy in any form. Energy in any form can only be transformed to some other forms of energy. This is known as conversion of energy.

In the context, the chemical energy that is produced by the battery and the electrical energy produced should be equal.

Answer:

Element Y,  or the third option

Explanation:

Alkanes are insoluble in water, but soluble in ether.  Their boiling points are pretty low, barely reaching 200 degrees, so element Y is an alkane.

Answer:

c.

Explanation:

Mass of iron chloride (FeCl₂) : 22.68 g

Proust stated the Comparative Law that compounds are formed from elements with the same Mass Comparison so that the compound has a fixed composition of elements

In the same compound, although from different sources and formed by different processes, it will still have the same composition/comparison

With this law, we can calculate how many grams an element is needed to make a compound with a certain mass, as desired

[tex]\tt mass~Fe=\dfrac{Ar~Fe}{MW~FeCl_2}\times mass~FeCl_2[/tex]

The iron ions in 50 g mixture :

[tex]\tt 20\%\times 50~g=10~g[/tex]

[tex]\tt 10=\dfrac{56}{127}\times mass~FeCl_2\\\\mass~FeCl_2=22.68~g[/tex]

Answer:

A.  5 N to the left

Note: The question is incomplete. The complete question is given below:

With a force of 5 newtons, Amanda pushes the stack of books to the right. At the same time, Jeremy, her little brother, pushes the stack of books to the left with a force of 10 newtons.

What is the direction and magnitude of the resulting force?

A.  5 N to the left

B.  5 N to the right

C.  10 N to the right

D.  10 N to the left

Explanation:

Forces are vector quantities.

Vector quantities are quantities that can be represented both in magnitude and direction.

Forces have both magnitude and direction. Forces can be directed positively or negatively.

For example, in the question above, if forces acting to the right are considered to be in the positive direction, forces acting to the left are considered to be acting in a negative direction.

In the addition of forces, both their magnitude and direction are taken into consideration.

In the example above, taking forces acting to the right as positive and to the left as negative, the sum of the forces is:

Resultant force, F = (5 N) + (-10N)

F = -5 N

Therefore, the net force is 5 N and is directed towards the left

Answer:

5 N to the left

Answer:

Explanation:

Aside the boiling point of water, another colligative property that can be used to identify pure water (or not) is the freezing point. Water freezes at 0 °C, but with the presence of impurities, there is a freezing point depression of the water. Thus, if the water is not pure, the liquid could freeze at a temperature lower than 0 °C (with a negative sign like -8 °C).

Answer: 177600 J or 177.6kJ

Explanation:

For this problem, we need to use q = mcAT

we have m = 10000, and AT= 40. The specific heat of iron is 0.444.

So now we can plug it in: q = 10000*.444*40 = 177600 J or 177.6kJ

Answer:

1848000J

Explanation:

Given parameters:

Mass of iron  = 100kg

Temperature change  = 40°C

Unknown:

Energy needed to increase the temperature  = ?

Solution:

The amount of energy needed is given by the expression below:

     H  = m C Δt

m is the mass

c is the specific heat capacity

Δt is the change in temperature

  c for iron is 462J/kg°C

 Now insert the parameters and solve;

  H  = 100 x 462 x 40  = 1848000J

Answer:

cylindar a

Explanation:

I took the test

Answer:

A

Explanation:

Answer: Crocodiles and tigers both have four legs

Explanation: Even when sharks and tigers are both meat eaters, the question is about similarities between tigers and crocodiles, so D is out. A is about crocodiles and sharks, so it's out also. B suits for sharks too, so it's out too. C is the most suitable answer, because both animals have four legs, which means that they belong to the group of quadrupede animals.

Answer:

Crocodiles and tigers both have four legs

Explanation:

A reaction comprises a reactant and a product. It is said to be in equilibrium when the rates for the forward and reverse reactions are equal. Thus, option D is correct.

An equilibrium reaction is a thermodynamic condition where the reactants and the products are at a stable position even before and after the reaction. They remain fixed and do not vary with the addition of any catalyst.

In the equilibrium position, the reaction rate of the forward (product formation) and reverse (reactant formation) remains the same and is seen in the reversible reactions only.

The amount of the products and the reactant remains constant till the temperature is constant but may vary if the tempearture is varied.

Therefore, the rate of reverse and forward are equal in the equilibrium reaction.

Learn more about equilibrium reaction here:

https://brainly.com/question/14926771

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Have the same number of protons but a different number of neutrons

The elements in nature have several types of isotopes

Isotopes are atoms whose no-atom has the same number of protons while still having a different number of neutrons.

So Isotopes are elements that have the same Atomic Number (Proton)

SO the Three Common Isotopes Of Oxygen :

₈¹⁶O, ₈¹⁷O, and ₈¹⁸O have :

1. The same number of protons = atomic number = 8

2. Have a different number of neutrons :(neutrons= mass number-atomic number)

₈¹⁶O : neutron = 16-8=8

₈¹⁷O : neutron = 17-8=9

₈¹⁸O : neutron = 18-8=10

Answer:

;l ok

Explanation:

Answer:

D

Explanation:

The amount increased to a certain point then decreased

Answer:

it is D

Explanation:

Answer:

10 g

Explanation:

The heating of copper can be represented by the following equation:

Cu + 1/2O2 ----> CuO

The new substance is copper oxide, CuO.

From the law of conservation of matter which says that matter can neither be created nor destroyed but be converted from one form to another, it means that barring any loss during heating, all the Cu should be converted to CuO. Hence, the amount of copper in the new substance should remain 10 g.

When it is in motion, i.e no longer stopped

Explanation:

If a ball is lifted to a certain height, it gains potential energy. If it is then dropped, the potential energy is converted into kinetic energy as it looses height but gains speed.

mass of the gas = 10 g

The law of conservation of mass :

In a closed / isolated system, the total mass of the substance before the reaction will be equal to the total mass of the reaction product.

Reaction

[tex]\tt X+Z\rightarrow gas+solution[/tex]

mass before reaction=mass after reaction

[tex]\tt 25+60=gas+75\\\\gas=25+60-75=10~g[/tex]

Volume of Argon = 59.972 L

In general, the gas equation can be written  

[tex]\large {\boxed {\bold {PV = nRT}}}[/tex]

where  

P = pressure, atm  

V = volume, liter  

n = number of moles  

R = gas constant = 0.08206 L.atm / mol K  

T = temperature, Kelvin  

At STP(0 C, 1 atm), 1 mol gas= 22.4 L

so for 20 L

[tex]\tt \dfrac{20}{22.4}=0.893[/tex]

For Argon

P = 1 atm

T = 273 K x 3 =819 K (tripled)

n = 0.893 (the same number of moles)

R = 0.082 L/atm.mol K

[tex]\tt V=\dfrac{nRT}{P}=\dfrac{0.893\times 0.082\times 819}{1}=59.972~L[/tex]

Answer:

4.01 g

Explanation:

Answer:

Explanation:

All periodic tables list different amounts of elemental masses. I'm going to round Sodium to 23

1 mol of sodium = 23

0.0467 mol sodium = x

Cross multiply

1*x = 0.0467 * 23

x = 1.0741 grams

Answer:

350 g BaSO₄

General Formulas and Concepts:

Chemistry - Stoichiometry

Explanation:

Step 1: Define

1.5 mol BaSO₄

Step 2: Identify Conversions

Molar Mass of Ba - 137.33 g/mol

Molar Mass of S - 32.07 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of BaSO₄ - 137.33 + 32.07 + 4(16.00) = 233.4 g/mol

Step 3: Convert

[tex]1.5 \ mol \ BaSO_4(\frac{233.4 \ g \ BaSO_4}{1 \ mol \ BaSO_4} )[/tex] = 350.1 g BaSO₄

Step 4: Check

We are given 2 sig figs. Follow sig fig rules and round.

350.1 g BaSO₄ ≈ 350 g BaSO₄