How do scientists test their ideas

Answer:

The answer is C... I am almost positive.

Answer:

Silicon

Explanation:

Silicon is in group IV with strong Si-Si ( Silicon to Silicon ) bonds. Since it is a molecule, these bonds exert a strong molecular force hence adopting a giant covalent structure.

T=41+273=314 k

M=(12)+(16×2)=44g/mol

d=PM/RT

d=685×44/0.0821×314

d=1169.15 g/L

Answer:

A positively charged nucleus consisting of protons and neutrons

Explanation:

The atomic nucleus is a positively charged region located at the core of an atom that consists of positively charged protons and neutral neutrons while the negatively charged electrons make up the outer cloud (electrons are therefore not contained in the nucleus).

Answer:

A. Mass percent composition of oxygen = 58.5%

B. Mass percentage composition of oxygen = 42.1%

C. Mass percentage composition of oxygen = 72.7 %

Explanation:

Percentage mass composition of an element in a compound is given by the formula below:

Percentage mass composition = mass of element/ molar mass of compound × 100%

Percentage mass of oxygen in the given compounds are then calculated.

a. Calcium nitrate, Ca(NO₃)₂: molar mass of compound is obtained first.

Molar mass of Ca(NO₃)₂ = 40 + 14 × 2 + 16 × 2 × 3 = 164 g

Mass of oxygen = 16 × 6 = 96 g

Mass percent composition of oxygen = 96/164 × 100% = 58.5%

b. Iron (ii) sulfate, FeSO₄: molar mass of compound is obtained first.

Molar mass of FeSO₄ = 56 + 32 + 16 × 4 = 152 g

Mass of oxygen = 16 × 4 = 64 g

Mass percentage composition of oxygen = 64/152 × 100% = 42.1%

c. Carbon dioxide, CO₂: molar mass of compound is obtained first.

Molar mass of CO₂ = 12 + 16 × 2 = 44 g

Mass of oxygen = 16 × 2 = 32 g

Mass percentage composition of oxygen = 32/44 × 100% = 72.7 %

Answer:

potentiol or kenetic

Explanation:

Answer:

6 atoms of carbon are in the reactant side

Explanation:

Are on the reactant side in:

6CO2 + 6H2O → C6H12O6 + 6O2

In the reaction, there are 6 molecules of CO2 that are reacting with 6 molecules of H2O. As you can see, CO2 has only 1 atom of carbon per molecule whereas H2O hasn't.

That means the atoms of carbon are:

6 molecules CO2 * (1atom C / 1molecule CO2) =

Answer:

95.9 kg

Explanation:

First we convert 15.0 mi² to m²:

Then we convert 27.0 ft to m:

Now we calculate the total volume of the lake:

Converting 3.20x10⁸ m³ to L:

Now we calculate the total mass of mercury in the lake, using the given concentration:

Finally we convert μg to kg:

Answer:

40.4 kJ

Explanation:

Step 1: Given data

Step 2: Calculate the moles corresponding to 55.0 g of CO₂

The molar mass of CO₂ is 44.01 g/mol.

n = 55.0 g × 1 mol/44.01 g = 1.25 mol

Step 3: Calculate the heat (Q) required to sublimate 1.25 moles of CO₂

We will use the following expression.

Q = n × ΔH°sub

Q = 1.25 mol × 32.3 kJ/mol = 40.4 kJ

Answer:

The given molecules are SO2 and BrF5.

Explanation:

Consider the molecule SO2:

The central atom is S.

The number of domains on S in this molecule is three.

Domain geometry is trigonal planar.

But there is a lone pair on the central atom.

So, according to VSEPR theory,

the molecular geometry becomes bent or V-shape.

Hybridization on the central atom is

[tex]sp^{2}[/tex].

Consider the molecule BrF5:

The central atom is Br.

The number of domains on the central atom is six.

Domain geometry is octahedral.

But the central atom has a lone pair of electrons.

So, the molecular geometry becomes square pyramidal.

The hybridization of the central atom is [tex]sp^{3} d^{2}[/tex].

The shapes of SO2 and BrF5 are shown below:

Answer:

Given total pressure of the gas mixture(hydrogen and helium) is 2.99 atm

Number of moles of hydrogen is ---- 13.2 mol

Number of moles of helium is ---- 19.1 mol

Determine the partial pressure of the helium gas.

Ratio of effusion rates of the two gases.

Explanation:

According to Dalton's law of partial pressures,

partial pressure of a component gas in a mixture is:

partial pressure of a gas = total pressure x mole fraction

mole fraction of helium gas is:

[tex]mole fraction of helium gas = \frac{number of moles of helium gas}{total number of mioles} \\=>mole fraction of He= \frac{19.1mol}{(19.1+13.2)mol} \\=>mole fraction of He = 0.591\\[/tex]

Partial pressure of He gas is:

[tex]Partial pressure of He =mole fraction of He * total pressure\\ =0.591 x 2.99atm\\ =1.77atm[/tex]

Effusion rate of a gas is inversely proportional to its square root of its molecular mass.

[tex]\frac{rate of effusion of H2 gas}{rate of effusion of He gas} =\sqrt{\frac{molar mass of He gas}{molar mass of H2 gas} } \\=> \frac{rate of effusion of H2 gas}{rate of effusion of He gas}=\sqrt{\frac{4g.}{2g} } \\=>\frac{rate of effusion of H2 gas}{rate of effusion of He gas}=1.414:1[/tex]

Hence, rates of effusion of H2:He is 1.414:1.

Answer:

1. B

2. A

3. C

4. C

5. D

Explanation:

Soil is regarded as the solid unconsolidated material of the earth crust. Soil is of three different types namely: Sandy soil, clay soil and loamy soil. These three different soil types possess different properties that distinguish them. Some of them are:

- CLAY soil is characterized as having the finest particles and can hold greater amount of water i.e. have a high water holding capacity.

- LOAMY SOIL is the best soil type for planting agricultural crops because it has the highest concentration of nutrients that suited for plant growth.

- loamy, Sandy and clay differ in how we feel when touched i.e. texture, and colour.

- SANDY soils are the kind of soils that are found in Sea shores and beaches.

- Soil is important to living things as it forms part of the earth where animals live, provides the necessary nutrients needed by plants, serves as a place where people live.

Answer:

36704 $

Explanation:

First we calculate how much the worker gets paid in one week:

Then we calculate how many weeks does the worker work in 1.7 years:

Finally we calculate how much does the worker make in 1.7 years:

Answer:

a) 2.9 mol

b) 19 atm

Explanation:

Step 1: Given data

Step 2: Calculate the number of moles (n) corresponding to 82 g of CO

The molar mass of CO is 28.01 g/mol.

82 g × 1 mol/28.01 g = 2.9 mol

Step 3: Calculate the pressure (P) inside the container

We will use the ideal gas equation.

P × V = n × R × T

P = n × R × T / V

P = 2.9 mol × (0.0821 atm.L/mol.K) × 298 K / 3.7 L = 19 atm

Answer:i believe you are to decompose the formula (i think)

Answer:

The correct answer is 0.020 M.

Explanation:

To solve this problem, we can use the equation M1V1 = M2V2, where M represents the molarity of the solution and V represents the volume of solution.  Since we are given that the original solution is 50 mL and 0.40 M, these values are V1 and M1, respectively.  The solution after dilution has a volume of 1000 mL, so this value is V2.  We are solving for the molarity after dilution, which represents M2.

If we plug in the values specified above, we get the following:

M1V1 = M2V2

(0.40 M)(50.0 mL) = (M2)(1000.0 mL)

Solving for M2, we get:

M2 = 0.020 M

Notice that our answer has 2 significant figures because 0.40 has 2 significant figures, the least of any values given in the problem.

Therefore, the answer is 0.020 M.

Hope this helps!

Answer:

when the explosion happened the matter fussed into elements as the electrons portions Nd notrons were compresed into the elements beacuase hydrogen has 1 nutron proton and electron surronding its core

Answer:

Everything around you can be broken down into smaller particles called atoms. The particles of one substance are all the same and different substances are made up of different particles.

Explanation:

Answer:

AgNO3 + KI → Agl + KNO3. Double-replacement reaction

Explanation:

Based on solubility rules, Silver, Ag produce an insoluble salt in presence of halides (Fluorides F-, Chlorides Cl-, Iodides, I-, and bromides Br-). That means the mixture of AgNO3 (Ag⁺ ions) with KI (I- ions) produce AgI as insoluble salt.

The reaction is:

And this is a double-replacement reaction where the cations exchange of anion to produce 2 new compounds.

Answer:

AgI + KNO3

Explanation:

double replacement

Transition metals

Most transition metals differ from the metals of Groups 1, 2, and 13 in that they are capable of forming more than one cation with different ionic charges. As an example, iron commonly forms two different ions

The question is incomplete, the complete question is:

A solution of permanganate is standardized by titration with oxalic acid. To react completely with 0.0018 mol of oxalic acid required 28.18 mL of permanganate solution. The unbalanced chemical equation for the reaction in acidic solution is:

[tex]\mathrm{MnO}_{4}^{-}(aq)+\mathrm{H}_{2}\mathrm{C}_{2}\mathrm{O}_{4}(aq)\stackrel{\mathrm{Acidic}}{\longrightarrow}\mathrm{Mn}^{2+}(aq)+\mathrm{CO}_{2}(\mathrm{g})[/tex]

Determine the concentration of the permanganate solution in molarity.

Answer: The molarity of permanganate solution is 0.026 M

Explanation:

The balanced chemical equation follows:

[tex]2MnO_4^-(aq)+6H^+(aq)+5H_2C_2O_4(aq)\rightarrow 2Mn^{2+}+8H_2O(l)+10CO_2(g)[/tex]

Given values:

Moles of oxalic acid = 0.0018 moles

By the stoichiometry of the reaction:

If 5 moles of oxalic acid reacts with 2 moles of permanganate solution

So, 0.0018 moles of oxalic acid will react with = [tex]\frac{2}{5}\times 0.0018mol=0.00072mol[/tex] of permanganate solution

Molarity is defined as the amount of solute expressed in the number of moles present per liter of solution. The units of molarity are mol/L. The formula used to calculate molarity:

[tex]\text{Molarity of solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (mL)}}[/tex] .....(1)

Given values:

Moles of permanganate solution = 0.00072 moles

Volume of solution = 28.18 mL

Putting values in equation 1, we get:

[tex]\text{Molarity of permanganate solution}=\frac{0.00072\times 1000}{28.18}\\\\\text{Molarity of permanganate solution}=0.026M[/tex]

Hence, the molarity of permanganate solution is 0.026 M

Evaporation can decrease the amount of water. Dust from the surroundings can enter the water. The water can freeze if the surrounding temperature decreases sufficiently.

Answer:

23.2 kJ of energy are released by the reaction.

Explanation:

Hello there!

In this case, according to the given information, it turns out firstly necessary for us to calculate the moles of both tin and nitrogen and the produced moles of Sn3N4 product by each reactant as shown below:

[tex]13.1gSn*\frac{1molSn}{119gSn} *\frac{1molSn_3N_4}{3molSn} =0.0367molSn_3N_4\\\\2.715gN_2*\frac{1molN_2}{28gN_2} *\frac{1molSn_3N_4}{2molN_2} =0.0485molSn_3N_4[/tex]

Thus, since 13.1 grams of tin produce the fewest moles of Sn3N4 product, we infer tin is the limiting reactant, and the correct produced energy, due to this reaction is:

[tex]E=632\frac{kJ}{mol\ rxn}*\frac{1mol\ rxn}{1molSn_3N_4}*0.0367mol Sn_3N_4\\\\E=23.2kJ[/tex]

Regards!

Answer:

D. having fur that is a similar color to tree barks with algae growing on it

Explanation:

Choice A doesnt make sense because sloths do not change colors, and hanging upside down would not protect you from prey or blend in. D matches the description of a sloth.

Answer:

Having fur that is a similar color to tree barks with algae growing on it.

Explanation:

Answer:

Colloids

There are two basic methods of forming a colloid: reduction of larger particles to colloidal size, and condensation of smaller particles (e.g., molecules) into colloidal particles. Some substances (e.g., gelatin or glue) are easily dispersed (in the proper solvent) to form a colloid; this spontaneous dispersion is called peptization. A metal can be dispersed by evaporating it in an electric arc; if the electrodes are immersed in water, colloidal particles of the metal form as the metal vapor cools. A solid (e.g., paint pigment) can be reduced to colloidal particles in a colloid mill, a mechanical device that uses a shearing force to break apart the larger particles. An emulsion is often prepared by homogenization, usually with the addition of an emulsifying agent. The above methods involve breaking down a larger substance into colloidal particles. Condensation of smaller particles to form a colloid usually involves chemical reactions—typically displacement, hydrolysis, or oxidation and reduction.