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Solnce55 [7]
2 years ago
13

Stest will not impact your grade.

Chemistry
2 answers:
andreev551 [17]2 years ago
8 0
Answer c space craft are built to be airtight.
Diano4ka-milaya [45]2 years ago
5 0
C. Spacecraft are built to be airtight.
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Explain how the bonding model for sodium metal would differ from the bonding model for sodium chloride, NaCi
Elina [12.6K]
Sodium metal is quite reactive; sodium ions (as in NaCl) are quite unreactive. Cl^- ions are not reactive; they are stingily attracted to positive ions such as Na^+with which they form ionic bonds.
8 0
3 years ago
If 0.600mol of chloride gas reacted with 0.500mol of aluminium metal to produce aluminium chloride,which reactant is in excess?h
alisha [4.7K]

Answer:

собак гандонов в гавне))))))))))

Explanation:

hloride,which reactant is in excess?how many moles of aluminium chloride can be produced during the reaction.hloride,which reactant is in excess?how many moles of aluсиськижопыссиськасуксиськипись loride can be produced during the reaction.hloride,which reactant is in excess?how many moles of aluminium chloride can be produced during the reaction.hloride,whichйух reactant is in excess?how many moles of aluminium chloride can be produced during the reaction.

5 0
2 years ago
Given the following information:Br2 bond energy = 193 kJ/mol F2 bond energy = 154 kJ/mol 1/2Br2(g) + 3/2F2(g) -> BrF3(g) = –3
arlik [135]

Answer:

C) 712 KJ/mol

Explanation:

  • ΔH°r = Σ Eb broken - Σ Eb formed
  • 1/2Br2(g) + 3/2F2(g) → BrF3(g)

∴ ΔH°r = - 384 KJ/mol

∴ Br2 Eb = 193 KJ/mol

∴ F2 Eb = 154 KJ/mol

⇒ Σ Eb broken = (1/2)(Br-Br) + (3/2)(F-F)

⇒ Σ Eb broken =  (1/2)(193 KJ/mol) + (3/2)(154 KJ/mol) = 327.5 KJ/mol

∴ Eb formed: Br-F

⇒ Σ Eb formed (Br-F) = Σ Eb broken - ΔH°r

⇒ Eb (Br-F) = 327.5 KJ/mol - ( - 384 KJ/mol )

⇒ Eb Br-F = 327.5 KJ/mol + 384 KJ/mol = 711.5 KJ/mol ≅ 712 KJ/mol

8 0
3 years ago
1. The basic building block of matter are atoms. Every atom is basically a tiny sphere. Every atom is composed of 2 regions, the
V125BC [204]

1. The answer is: Electron cloud.

Atom is composed of the nucleus and the electron cloud.

Protons (positive particles) and neutrons (neutral particles) are in the nucleus of an atom and electrons (negative particles) are in the electron cloud.

Nucleus is in the centar of the atom atom and electron cloud is surrounding it.

2. The answer is: Electron(s).

The electron (symbol: e⁻) is a subatomic particle whose electric charge is negative one elementary charge.

Metallic bond increace electrical and thermal conductivity.

Substances with metallic bond conduct an electric current in liquid and solid state, because they have mobile electrons. Most metals have strong metallic bond, because strong electrostatic attractive force between valence electrons (metals usually have low ionization energy and lose electrons easy) and positively charged metal ions.

3. The answer is: Nucleus.

Atomic number (Z) is total number of protons and mass number (A) is total number of protons and neutrons in a nucleus.

Nucleus of an atom has positive charge, electrons are negative and atom has neutral net charge.

For example, alpha particle is nucleus of a helium-4 atom, which is made of two protons (p⁺) and two neutrons (n°).

4. The answer is: Proton(s).

The proton (p⁺) is subatomic particle with a positive electric charge of +1e elementary charge.

Protons and neutrons, each with masses of approximately one atomic mass unit, are called nucleons.

Protons and neutrons are hadrons composed of three valence quarks.

The electron has a mass that is approximately 1/1836 that of the proton and the neutron.

5. The answer is: Neutron(s).

Neutron (symbol: n°) is a subatomic particle with no net electric charge.

Protons and neutrons are found in nucleus of an atom (atomic nuclei).  

They are called nucleons and have masses of approximately one atomic mass unit.

Mass number (A) is sum of protons and neutrons in nucleus of an atom.

6. The answer is: Direct relationship.

For example, the Hertzsprung–Russell diagram shows the relationship between the star's absolute luminosities (the total amount of energy emitted per unit of time by a star) versus their effective temperatures (the temperature of a black body that would emit the same total amount of electromagnetic radiation).

The Hertzsprung–Russell diagram puts each star on a graph according the star's brightness against its temperature.

7. The answer is: Inverse relationship.

For example, Wavelength is the inverse of the frequency.

Wavelength is the distance over which the wave's shape repeats.

The frequency is a measure of how often sinusoidal components of the wave repeat per unit of distance.  

Higher the frequency, shorter the wavelenght.

Shorter the frequncy, longer the wavelenght.

8. The answer is: No relationship.

Correlation is any statistical association, how close two variables are to having a linear relationship with each other.

If the correlation between the two variables is zero, there is no relationship

between them. So, variables have nothing to do with each other.

9. The answer is: Experimental control.

An experimental control is used in scientific experiments to minimize the effect of variables which are not the interest of the study.

The two main variables in an experiment are the independent and dependent variable.

Dependent variable is the variable being tested and measured in a scientific experiment.

Dependent variables depend on the values of independent variables. The dependent variables represent the output or outcome whose variation is being studied.

10. The answer is: Controlled variable(s).

A control variable is an experimental element which is constant and unchanged throughout the course of the experimentation.

For example, if the volume is made the control variable, it is not allowed to change it throughout the course of the experiment.

The control variables are not of primary interest to the experimenter.

7 0
3 years ago
Polyglutamate also exhibits pH-dependent unfolding. This transition occurs at a pH of about 7; below that pH the polypeptide cha
Novosadov [1.4K]

Answer:

Explanation:

As the pH drops, the NH2groups on the lysine side chains become charged and helices can no longer form because of charge repulsion between these groups. This might occur below the pKa of lysine if more than 50% of the lysine residues is to be charged in order to ‘break’ the helix. Another possibility is that the pKa of lysine residues might be different when in polylysine as compared with the monomer (free amino acid) in solution.

One will expect other residues that are positively charged at neutral pH to have a similar profile; namely, arginine and possibly histidine. Both arginine and histidine are bulkier than lysine. Even if there were some rotation of their side chains, steric interference would probably be so severe as to prohibit the formation of an -helix. The transition is inverted because at a low pH glutamate will be neutral whereas at a high pH it will assume a net negative charge (through dissociation of the carboxyl groups on its side chains). One will easily speculate that a polypeptide chain containing both glutamate and lysine residues will be able to form an helix at relatively neutral pHs. Under these conditions, lysines will be mostly positively charged and glutamates will be mostly negatively charged. This will allow these residues to make ionic bonds and salt bridges to stabilize the helix. At very low pH, however, lysine will be mostly positively charged, but it will be near to neutral glutamate residues. At very high pH, the Glu will be negatively charged, but it will be near neutral.

5 0
3 years ago
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